Technical multi-stakeholder report on Internet shutdowns: The case of Iran amid autumn 2022 protests

OONI, IODA, M-Lab, Cloudflare, Kentik, Censored Planet, ISOC, Article19 2022-11-29

This report shares empirical technical findings on the recent Internet shutdown events that emerged in Iran following the death of Jhina (Mahsa) Amini in September 2022. The report is intended to be the first among a series of multi-stakeholder reports aimed at shedding light on what is becoming a widespread and increasingly sophisticated practice of certain governments around the world. The stakeholders participating in the report share a concern about the global trend in Internet shutdowns, but are contributing to the analysis only on the basis of their technical expertise.

Over the years, Iranian authorities have followed a pattern of blocking social media apps, numerous websites and even resorting to shutting networks entirely, implementing overall pervasive levels of Internet control. The latest shutdown events that emerged in Iran in September 2022 amid ongoing protests follow the same pattern, but show a wider range of technical strategies to prevent censorship circumvention.

Summary of Key Findings

Iran has implemented pervasive Internet censorship for years. Following the death of Jhina (Mahsa) Amini and widespread protests, new forms of Internet censorship and shutdowns emerged in Iran. This report combines multiple network measurement datasets to investigate the recent Internet censorship and shutdown events in Iran. The findings of this report are based on the analysis of measurements between 16th September 2022 to 16th October 2022.

Public measurement datasets show the following new censorship events in Iran:

DisruptionTimingDetailsImpact
Mobile network outages (IODA, Cloudflare, Kentik)Between 21st Sept. to 3rd Oct. from 4 PM to midnight daily, and again on 8th, 12th, and 15th Oct.The Iranian government enacted a “digital curfew” by shutting down access to 3 major mobile networks (Irancell, Rightel, and MCCI) in the evenings.Users on these networks lost all Internet connectivity. They could access the Internet only through fixed-line or satellite providers. This may have had a severe impact on protest documentation.
Regional Internet outages (IODA, Cloudflare)Kurdistan province: 19th Sept and 8th-9th Oct (afternoon/ evening) Khuzestan province: 16th Oct (all day)Disruptions to Internet services were observed on multiple days in September and October in Kordestan and Khuzestan. Protests following Jhina Amini’s death were particularly heavy in this province, and protest repression is always treated with far higher levels of severity in these regions dominated by Iran’s ethnic minorities (Iran’s Kurdish and Ahwazi minorities).Users on affected networks in the affected regions lost all Internet connectivity. They could access the Internet only through alternative providers. This, too, may have had a severe impact on protest documentation.
Blocking of HTTP/3 and QUIC traffic (Cloudflare)22nd Sept. onwardHTTP/3 is the latest version of the protocol for transferring web data. It relies on QUIC, a similarly recent low-level protocol. Both QUIC and HTTP/3 traffic dropped to near zero, suggesting a blanket block on QUIC.When these protocols are blocked, users lose the performance and security benefits that they offer. Existing tools may be better at inspecting and filtering traffic on older protocols, so blocking them would also make users more vulnerable to targeted filtering.
IPv6 disruption (OONI, Cloudflare)22nd Sept. to 2nd Oct.Traffic using the newer IPv6 networking protocol dropped substantially on Irancell, which could indicate the protocol was blocked.It is unclear what implications this would have for most users.
Increased blocking of encrypted DNS (OONI)20th Sept. onwardMany ISPs in Iran increased the blocking of secure domain name resolution servers (DNS over HTTPS, or DoH) by several technical means (interference with DNS and TLS).DoH helps circumvent censorship by encrypting the names of the websites a user is visiting. Network administrators then cannot see when a website or service they want to block is being accessed by name. Blocking DoH thus makes circumvention harder.
Increased throughput for mobile networks (M-Lab)21st Sept. onwardThroughput of mobile networks (Mobile Communication Company of Iran PLC and Irancell) increased from 10-15 Mbps to 20 Mbps.Mobile users experienced higher transfer speeds, potentially as the result of increased cellular base station infrastructure (which may also be used for finer grained surveillance).
Blocking of social media and messaging platforms (OONI)WhatsApp and Instagram: 21st Sept. onward Skype, Viber and LinkedIn: 23rd Sept. onwardMany ISPs in Iran started blocking WhatsApp and Instagram. A few days later, they also started blocking Skype, Viber, and Linkedin.Even when Internet connectivity was available, users could not use these communication services without circumvention tools (e.g., VPNs).
Blocking of app stores (OONI)22nd Sept. onwardMultiple ISPs in Iran started blocking access to the domain names for the Google Play Store and Apple App Store.Affected Iranians would have had difficulty installing or updating apps, including apps that provide relevant socio-economic services and censorship circumvention tools.
Blocking of browser extension repositories (OONI)26th Sept. (or earlier) and onwardMultiple ISPs in Iran blocked the browser extension repository URLs for Firefox, Chrome, Microsoft Edge and Opera.Affected Iranians would have had limited ability to install and update browser extensions, including extensions that provide privacy protection and censorship circumvention capabilities.

These findings are visualized through the following image, which provides a timeline of shutdown events in Iran (between 16th September and 16th October 2022) following the death of Jhina (Mahsa) Amini.

Image: Timeline of events in Iran between 16th September 2022 to 16th October 2022.

Economic indicators (gathered by ISOC) make clear that Iran’s economy suffered during the period of the shutdowns. Nighttime light output was down, the stock market saw a steady decline, and imports/exports were down slightly.

These economic changes may have been caused or exacerbated by the shutdowns themselves. All of these data points are correlational, not causal. Drawing strong conclusions about causality would require far more data over an extended period. In the case of Iran, some of this data is hard, if not impossible, to obtain. For example, in this case public opinion data about the shutdown would be valuable to gauge the on-the-ground effects, but that data is not currently available. Still, the shutdowns present a plausible explanation for at least some of the economic variation, which future analysis may be able to confirm.

The evidence demonstrating these events and conclusions is described in detail in the sections below.

Disruptions to Network Infrastructure

Mobile Network Outages

In the wake of the death of Jhina (Mahsa) Amini on 16th September 2022, protests erupted in Iran. With this mobilization came daily shutdowns to Iran’s top 3 mobile network providers: Irancell, Rightel, and MCCI.

For 13 consecutive days, from 21st September 2022 to 3rd October 2022, the Iranian government enacted a “digital curfew” by shutting down access to mobile networks from 4:00 PM local time until around midnight. Over the 13 day period, Iranians experienced ~100 hours without access to mobile networks. Mobile networks were again shut down on 8th, 12th and 15th October 2022.

These outages are visible through telemetry provided by the Internet Outage Detection and Analysis (IODA) project, shown in Figure 1.

Figure 1: IODA data showing Internet outages in Iran between 16th September 2022 to 16th October 2022 (source: IODA). The red vertical bands indicate outages, which are detected as abnormal drops in the green “BGP” signal. The BGP data source represents routing announcements or global routing information that each ISP router exchanges with other routers, and it is usually quite stable. An abnormal drop can indicate a disruption in Internet connectivity. During the digital curfews, the blue Active Probing and purple Google search signals (see Methods below) are not reaching the maximums they normally would. (IODA’s “telescope” signal is removed from the time series for this view as it does not provide additional information.)

The IODA chart in Figure 2 shows the daily outages observed on RighTel between 18th September 2022 to 5th October 2022.

Figure 2: IODA data showing BGP signal for mobile operator RightTel between 18th September 2022 to 5th October 2022 (source: IODA). As in the previous figure, the red vertical bands indicate outages as evidenced by abnormal drops in the green BGP signal.

Similarly, IODA data shows daily outages on Irancell between 18th September 2022 to 5th October 2022.

Figure 3: IODA data showing the “Telescope” signal for mobile operator IranCell between 18th September 2022 to 5th October 2022 (source: IODA). The graph shows red vertical bands for abnormal drops in the Telescope signal. Telescope is a measure of unsolicited network traffic on a network (see Methods). An abnormal decrease in Telescope could indicate a drop in Internet connectivity.

The timing and the networks affected by outages in Iran are corroborated by Cloudflare Radar data (Figure 4), which also shows traffic drops from Irancell, RighTel and MCCI.

Figure 4: Graph showing Cloudflare traffic volumes for Irancell (green), Rightel (yellow), and MCCI (red) between 18th September 2022 and 16th October 2022 (source: Cloudflare Radar).

The Cloudflare Radar graph shows not only that traffic on these network providers was disrupted for several hours each day, but also that traffic was significantly higher than pre-shutdown levels each day after connectivity returned.

The mobile network outages are further corroborated by Kentik data (Figure 5), which shows daily drops in traffic from Irancell, MCCI, and RighTel during the same date range.

Figure 5: Graph showing Kentik traffic volumes for the Iranian three mobile carriers Irancell (dark green), Rightel (yellow), and MCI (light green) between 18th September 2022 and 5th October 2022 (source: Kentik).

Additionally, Kentik’s data show increases in traffic on fixed-line services in Iran during the outages of mobile networks (Figure 6), suggesting that a small portion of the Internet traffic lost due to mobile blockages was rerouted over fixed-line services.

Figure 6: Graph showing Kentik traffic volumes for Iran’s largest wireline carrier (TCI, in blue) surging during shutdowns of Iran’s largest mobile carrier (Irancell, in green) between 22nd September 2022 and 28th September 2022 (source: Kentik).

Comparison to Previous Outages

Iran has previously experienced Internet outages during protests. Amid the November 2019 protests, Iran implemented a nationwide Internet shutdown. During the shutdown, most Iranians were barred from connecting to the global Internet, but they still had access to Iran’s national intranet (the domestic network hosting Iranian websites and services).

The main differences between the recent Internet outages in Iran with the nationwide Internet shutdown in November 2019 are:

Regional Outages

In addition to above network shutdowns with country-wide scale, IODA data, corroborated by Cloudflare data, demonstrates signs of Internet disruption impacting the Kordestan and Khuzestan provinces (see dates and times in table below with hyperlinked images to IODA data views). The IODA graphs show BGP (green), Active Probing (blue), and Telescope (orange) signals; the Cloudflare graphs show HTTP requests per second. The dip in traffic in the last Cloudflare graph is indicated by the red arrow.

HTTP/3 and QUIC Traffic Drop

HTTP, the foundation of the World Wide Web that allows users to request data and documents from servers, rests on many underlying protocols for lower-level functionality (e.g., transmitting raw data). HTTP/3 is the latest revision of this protocol. Instead of using the more traditional TCP and TLS protocols for transport and security, HTTP/3 is based on UDP and QUIC. Since it is relatively new and uses a quite different networking stack, it is likely that existing filtering equipment is not as effective at blocking it.

On 22nd September 2022, Cloudflare Radar data shows a drop to near-zero level of HTTP/3 and QUIC traffic coming from Iran, as shown in Figure 7.

Figure 7: Cloudflare Radar graphs showing distribution of traffic by the three different HTTP versions and distribution of secure traffic by protocol for Iran (source: Cloudflare Radar).

This strongly suggests that QUIC, which HTTP/3 relies on, was blocked entirely, perhaps by blocking UDP port 443. It is possible that network operators in Iran found it easier to block all QUIC traffic than to effectively implement targeted filtering on the newer QUIC protocol. This is supported by previous research that shows a difference in blocking for HTTP/3 vs HTTPS traffic.

IPv6 disruption on Irancell

IPv6 is the latest version of the Internet Protocol, the low-level protocol that enables computers to find each other by their “IP address” and send and receive data. It supersedes the older IPv4. OONI measurements suggest that Irancell may have interfered with IPv6 traffic from 22nd September 2022 to at least 29th September 2022. Within this period, OONI measurements collected from Irancell (Figure 8) show that while attempts to connect to IPv4 addresses succeeded, attempts to connect to IPv6 addresses failed.

Figure 8: OONI attempts to make TCP connections using IPv6 in Irancell, showing failures starting on 22nd September 2022.The few measurements annotated in purple pertain to cases where OONI Probe users did not have IPv6 support.

Figure 8 shows that before 22nd September 2022, the majority of the attempts succeed, but from 22nd September 2022 onwards, the majority of the attempts result in connection timeouts. This suggests that IPv6 was not reachable on Irancell.

This is further suggested by Cloudflare Radar data (Figure 9), which shows a drop in IPv6 traffic on Irancell during the same period.

Figure 9: Cloudflare Radar graph showing distribution of traffic by IP version for Irancell (source: Cloudflare Radar).

These results are further corroborated by “ping” measurements of a RIPE Atlas probe towards the IPv6 address of a root DNS resolver (Figure 10). These measurements indicate how long it took a device in Iran to reach a server providing a core global service for IPv6.

Figure 10: Ping measurements towards the IPv6 address of one of the a.root-servers.net root DNS resolver (source: RIPE Atlas). Red blocks indicate times when the resolver’s IPv6 address could not be reached.

Kentik data shows similar disruptions in traffic volume to IPv6 addresses (Figure 11).

Figure 11: Graph showing Kentik traffic volumes for IPv6 only for the Iranian three mobile carriers Irancell (dark green), Rightel (light green), and MCI (yellow) between 18th September 2022 and 5th October 2022 (source: Kentik).

It remains unclear what implications IPv6 blocking would have had for users.

Increased blocking of encrypted DNS

The Domain Name Service (DNS) is how Internet devices map from names (e.g., www.example.com) to IP addresses. In recent years, encrypted DNS was introduced to make users’ Internet traffic more private and secure, and to make it harder for governments to monitor and block access to Internet services. Encrypted DNS works by exchanging the DNS data over secure protocols such as TLS and HTTPS, preventing authorities or others from seeing the names of requested websites and services or interfering with the DNS results.

In 2020, however, OONI reported that Iran blocked DNS over TLS (DoT). At the time, OONI found that 57% of the tested endpoints were blocked on at least one ISP, and that most blocking was implemented by interfering with the TLS handshake, i.e., ISPs were preventing a secure connection from being established. A subsequent OONI study found that 50% of tested DoT endpoints were blocked in Iran, while 92% of tested DNS over HTTPS (DoH) endpoints worked in Iran. These studies involved users within Iran testing publicly available DoH and DoT servers that were operated globally outside of Iran.

The situation changed in September 2022, when OONI data started to show increased blocking of encrypted DNS in Iran. As of 20th September 2022, OONI data shows that ISPs in Iran started blocking DNS over HTTPS (DoH) endpoints by means of DNS based tampering, in addition to implementing TLS level interference. Previously reachable DoH endpoints (such as cloudflare-dns.com) are now blocked.

Figure 12: OONI data on the blocking of popular DNS over HTTPS endpoints in Iran between August 2022 to September 2022 (source: OONI MAT).

Figure 12 aggregates OONI measurement coverage from the testing in Iran of multiple DoH endpoints. These measurements are aggregated from multiple tested networks in Iran. OONI measurements are annotated as “OK” (green) when the tested URL is considered to be accessible on a tested network according to OONI’s Web Connectivity methodology.

Measurements are annotated as “anomalous” (orange) when the tested URL fails to meet the Web Connectivity methodology requirements for accessibility, indicating potential blocking. Measurements are annotated as “confirmed” (red) when blocking is automatically confirmed. OONI is able to automatically confirm blocking based on the fingerprints of blockpages, or when DNS resolution returns an IP known to be associated with censorship. When URLs are blocked through the use of other censorship techniques, those measurements are annotated as “anomalous” (because their blocking cannot be confirmed automatically). Finally, OONI measurements are annotated as “failed” when the experiment fails (this can be due to blocking, bugs, or other reasons).

As of 20th September 2022, OONI data collected from Iran shows a noticeable change in how the blocking of encrypted DNS is implemented. Previously, OONI data showed TLS level interference (annotated in orange as “anomalous”), whereas now, most (tested) ISPs implement DNS based blocking of DoH endpoints as well. These blocking cases are automatically confirmed (and annotated in red). OONI data also shows that this block has been expanded to more DoH endpoints than in previous months.

The impact of DoH blocking in Iran is also evident through Cloudflare data (Figure 13), which also shows that it started on 20th September 2022.

Figure 13: Traffic to Cloudflare 1.1.1.1 resolver from clients in Iran (source: Cloudflare).

As a result of the increased blocking of encrypted DNS services, circumventing Internet censorship in Iran – a heavily censored environment – may now be harder.

Impact on Internet Speed Tests

When users had at least some Internet connectivity, they were able to connect to network diagnostic tests such as M-Lab’s. Since mid-September 2022, M-Lab data shows a marked increase in daily tests from 5 Iranian ISPs, particularly for Iran Telecommunication Company PJS and Irancell. Figure 14 shows the daily diagnostic test volumes for the five Iranian providers with the most tests observed in the M-Lab dataset.

Figure 14: Number of speed tests per day since September 1, 2022 for five ISPs. Iran Telecommunication Company PJS (AS58224) is shown in orange; Irancell (AS44244) is shown in purple. (Source: M-Lab).

Zooming in on tests per hour for these five networks reveals the impact of periodic shutdowns on test activity. The figure below shows hourly test volume for mobile networks (left) and fixed-line ISPs (right). Both types of networks exhibit periodic shutdown behavior, but with differing periodicity.

Figure 15: Hourly test volume for speed tests (9/25/2022-10/05/2022), separating out mobile networks (top chart) and fixed line ISPs (bottom chart). (Source: M-Lab).

Based on the quantity of speed tests, it can be inferred that users are concerned about their network connectivity and navigate to the speed test to check their access. However, despite reports of network interference, M-Lab data shows that when users were able to connect to the global Internet to run the speed test, they saw a sustained increase in network throughput on Irancell and Mobile Communication Company of Iran PLC, both cellular network providers (Figure 16). This could be as a result of increased deployment of cell towers (e.g., to make more precise observations of mobile subscriber IDs), but we are currently unable to verify this hypothesis.

Figure 16: Median daily throughput for speed tests from Iran, 2022. There is an increase in median throughput for cellular carriers Mobile Communication Company of Iran PLC (AS197207) and Irancell (AS44244). (Source: M-Lab).

M-Lab data does not show discernible changes in network latency or loss for Iranian clients of the speed test.

Targeted Disruptions to Apps and Services

Iran has blocked numerous websites and apps over the past decade, implementing some of the most pervasive forms of Internet censorship in the world. In 2017, OONI published a report based on the analysis of network measurements collected from Iran between 2014 to 2017. This study found numerous news media websites, human rights websites, and political websites blocked in the country. Subsequent studies also show the blocking of numerous LGBTIQ websites in Iran.

Amid anti-government protests between December 2017 to January 2018, OONI reported on the blocking of Telegram, Facebook Messenger, and Instagram in Iran. In March 2020, Iran temporarily blocked access to the Farsi language edition of Wikipedia. In January 2021, Iran started blocking access to the Signal Private Messenger app. While many of these (and other) blocks remain ongoing, OONI data shows that Iran increased the levels of Internet censorship following the September 2022 protests: more ISPs now block access to more platforms, as shown below.

Blocking of WhatsApp, Instagram, Skype, Viber and Linkedin

As of 21st September 2022, OONI data shows that many ISPs in Iran started blocking access to WhatsApp endpoints, web.whatsapp.com, and www.instagram.com. In most cases, OONI data shows signs of TCP/IP blocking (disrupting connections with and data transfer to/from the server), with additional blocking via DNS (preventing users from retrieving an IP address for the server’s domain name) and TLS (preventing users from securing their connections with the server). As of 23rd September 2022, OONI data shows the blocking of Skype and Viber, while the blocking of Linkedin is automatically confirmed on at least 10 networks in Iran.

Figure 17: OONI data on the testing of WhatsApp Web, Instagram, Viber, Linkedin and Skype in Iran between September 2022 to October 2022 (source: OONI MAT).

Figure 17 aggregates OONI measurement coverage from the testing of WhatsApp Web, Instagram, Linkedin and Skype on multiple networks in Iran between 6th September 2022 to 5th October 2022. As is evident from the chart, both WhatsApp Web and Instagram were previously accessible on most tested networks in Iran, and only started to present signs of blocking from 21st September 2022 onwards. Meanwhile, the testing of Skype, Viber, and Linkedin started presenting signs of blocking on multiple networks two days later, on 23rd September 2022.

Similarly, OONI data suggests that Iran started blocking access to the WhatsApp app on 21st September 2022 (Figure 18).

Figure 18: OONI data on the testing of WhatsApp in Iran between September 2022 to October 2022 (source: OONI MAT).

The figure aggregates OONI measurement coverage from the testing of WhatsApp endpoints on multiple networks in Iran between 6th September 2022 to 5th October 2022. It is evident that while WhatsApp was previously accessible on most tested networks in Iran, it started presenting signs of blocking on almost all tested networks from 21st September 2022 onwards.

Kentik data confirms that traffic volume from Facebook’s network, which would include WhatsApp traffic, dropped substantially on 21st September 2022 (Figure 19).

Figure 19: Graph showing Kentik traffic volumes from Facebook (AS32934) to the Iranian three mobile carriers Irancell (dark green), Rightel (yellow), and MCI (light green) between 18th September 2022 and 5th October 2022 (source: Kentik).

Blocking of Google Play Store and Apple App Store

As of 22nd September 2022, OONI data shows that multiple ISPs in Iran started blocking access to Google Play Store and Apple App Store domains, limiting Iranians’ ability to install or update apps.

Figure 20: OONI data on the testing of Google Play Store and Apple App Store domains in Iran between September 2022 to October 2022 (source: OONI MAT).

Figure 20 aggregates OONI measurement coverage from the testing of Google Play Store and Apple App Store domains on multiple networks in Iran between 6th September 2022 to 5th October 2022. From 22nd September 2022 onwards, OONI data shows a spike in measurements presenting both “anomalies” (signs of blocking) and those where the block is automatically confirmed. Notably, the blocked domains include play.googleapis.com, which is one of the key domains used by Google Play Store.

Blocking of Browser Extension Repositories

Beyond the blocking of app stores, OONI data suggests that Iran started blocking several browser extension repositories, limiting Iranians’ ability to install and update browser extensions.

Figure 21: OONI data on the testing of browser extensions in Iran between September 2022 to October 2022 (source: OONI MAT).

Figure 21 aggregates OONI measurement coverage from the testing of the browser extension repository URLs for Firefox, Chrome, Microsoft Edge and Opera from multiple networks in Iran between 6th September 2022 to 5th October 2022. Most URLs from the figure lack testing coverage before 26th September 2022 because they were only added to the list of tested websites on that date. Given that access to addons.mozilla.org was blocked on 24th September 2022, it is possible that ISPs may have started blocking access to the other URLs on the same day (if they synchronized the blocking of browser extension repositories).

It is worth highlighting that all of the above tested URLs were automatically confirmed blocked when tested on multiple networks in Iran from 26th September 2022 onwards.

Circumvention Tools

Internet censorship can be evaded through the use of circumvention tools. However, numerous circumvention tool websites have been blocked in Iran over the past years, as demonstrated through OONI data.

Figure 22 aggregates OONI measurement coverage from the testing of circumvention tool websites on multiple networks in Iran between 18th August 2022 to 17th October 2022.

Figure 22: OONI data on the blocking of circumvention tool websites in Iran between 18th August 2022 to 17th October 2022 (source: OONI MAT).

As is evident from the chart, numerous circumvention tool websites have been blocked in Iran before the recent protests.

The blocking of circumvention tool websites in Iran is further corroborated by Censored Planet data (Figure 23).

Figure 23: Censored Planet data on the blockage of circumvention and VPN provider websites in Iran as of October 14, 2022 (source: Censored Planet).

Censored Planet measured the reachability of these circumvention tool providers’ secure websites, as of 14th October 2022, from 13 vantage points behind 7 ISPs inside Iran. Probes trying to reach popular circumvention websites such as the torproject.org and VPN provider websites have all been blocked across the tested networks. While the majority of the networks block webpages by timing out the low-level TCP request, the AFRANET network performs the blocking by resetting TCP requests.

While circumvention tool websites have been blocked in Iran for years, the extent to which ISPs in Iran are able to successfully block the actual circumvention tools is less clear – particularly since some circumvention tools include built-in techniques for evading censors.

OONI data suggests that the Psiphon and Tor Snowflake circumvention tools may work in Iran, and can potentially be used for censorship circumvention. While OONI tests indicate that it is possible to bootstrap these tools from Iran and use them to fetch a small webpage, there is no public data available on whether these tools are effective in providing circumvention for long periods of time. It is worth noting though that both Psiphon and Tor Metrics show a spike in the number of users connecting from Iran in September 2022, suggesting increased circumvention attempts following more pervasive forms of Internet censorship in Iran.

The Economic Impact of Iran’s Internet Shutdowns

Measuring the impact of a shutdown like the ones in Iran presents a unique challenge. There are many kinds of “impact,” ranging from economic to social to, political, to daily-life in Iran. This section will focus on the economic impact, which itself has many facets.

Measuring Economic Activity With Light Output

One dataset that economists have been using recently to measure economic activity is satellite imagery of the nighttime light output of a given geographic area. Nighttime light output has been found to correlate with how economically active a region’s population is during the timeframe observed.

ISOC’s data comes from the low-light imaging sensor on NASA’s Suomi National Polar-orbiting Partnership (S-NPP) satellite. This is part of the Visible Infrared Imaging Radiometer Suite (VIIRS), and is called the Day/Night Band (DNB).

The video below shows that nighttime light intensified from 16th September 2022 through 3rd October 2022 in Tehran. Over the following days, nighttime lighting dropped below its initial levels, which could indicate Iranians became less active as the government crackdown intensified and movement was restricted in the region. The drop in lighting could be a lagging indicator of reduced economic activity due to both Internet shutdowns and night curfews on movement, though the nature and timing of these effects is confounded by potential lighting increases from widespread nighttime protests.

Video: ISOC Impact Shutdown - Tehran (Night-time lights data 16th Sept.-16th Oct).

This analysis demonstrates the difficulties in measuring the impact of a shutdown. Nighttime lights provide valuable insights where robust statistical systems may be absent, and economists typically use them to map impacts of sudden policy changes (e.g., COVID-19 restrictions). Since this is the first attempt to link nighttime lights in the context of an Internet shutdown, various confounding effects cannot be ruled out. However, without this analysis we would be uncertain about the potential of nighttime lights to explore potential correlation with shutdowns. While we can infer from the reduction in light that Iranians are changing their use of personal appliances (e.g., lights, mobile phones, TVs) and public lighting (e.g., street lights), there is no way to make a causal link directly to the shutdown, and simultaneous events muddy the analysis. In order to conclude that there was a drop in economic productivity, we would also need information on the “business-as-usual” number of productive hours (e.g., if economic activity is not regulated during the night time, as it may be in certain jurisdictions).

A second video from the Sistan and Baluchestan region shows a similar pattern. This is the region that has seen the most fatalities in Iran during the recent protests and associated shutdowns. There is a marked decline in luminosity as of 3rd October 2022. This is a capture of a larger region than the Tehran image above, and shows certain areas within the province going completely dark following a period of intensified activity leading up to 3rd October 2022.

Stock Market Indicators

The stock market is another commonly used indicator of a country’s economic output and health. This data is theoretically available yet at a finer-grained timescale: even within a day, any stock market can have swings between the opening and closing bell. The charts in Figure 24 show only day-level data, but they clearly indicate that Iran witnessed a steady drop in stock market performance during the shutdowns. Again, the shutdowns plausibly played a role here, although it is difficult to disentangle their impact from other factors such as general political instability.

Figure 24: Changes in Stock Market Performance in Iran between 10th September 2022 to 12th October 2022 (Source: Tehran Stock Exchange Main Index (TEDPIX), ISOC). See the Technical Details section below for individual datasets.

Iran Import/Export Indicators

Another indicator of the health of a country’s economy is trade data. One way to measure trade in a region is to measure how many cargo ships deliver and receive goods at major ports. In the case of Iran, there are many major ports whose data we can explore to understand economic activity. This can add information beyond stock market data, which is subject to fluctuations and may only capture a component of the impact of business and corporate activity in the country.

Data on exports and imports by volume of goods is presented in Figure 25. Viewing just the data for September 2022 or October 2022 may provide an incomplete picture, since we need to know how much trade has changed relative to business-as-usual. To capture this, we need to look at how much trade is taking place following the shutdown relative to how much trade would normally take place during this time.

The data presented below shows the ratio of the current imports and exports data to their values averaged during the 2017-19 period. There is a decline in shipping containers moving out from Iran, and a decline in bulk and food coming into the country’s ports. As with earlier data, this is correlational, not necessarily causal, as we see changes in the types of exports (e.g., more oil and chemicals being exported), and a small increase in overall container imports following the current Internet shutdown in Iran. This suggests that Internet shutdowns may have hampered logistics associated with trade (e.g., lack of timely communication about arrivals at ports), where certain trade in specific trade operations were more adversely affected than others in Iran.

Figure 25: Trade Data on Imports and Exports in Metric Tons (Relative to 2017-2019) for Iran. See the Technical Details section for individual datasets.

Conclusion

Iran has had a tight grip on the Internet for years, implementing pervasive levels of Internet censorship (blocking numerous websites and major apps). Over the years, as anti-government protests emerged (such as the protests in late 2017 and November 2019), Iranian authorities have followed a pattern of blocking social media apps that Iranians rely on for communication, information sharing, and coordination—even resorting to shutting networks down entirely.

Amid the ongoing protests following the death of Jhina (Mahsa) Amini, the Internet shutdown events in Iran have followed the same pattern, involving the blocking of social media platforms and mobile network outages. What differs, though, is the duration and scale of the impact, as well as the fact that these shutdowns were implemented in an already heavily censored environment.

While major instant messaging platforms (such as Telegram, Facebook Messenger, and Signal) were already blocked prior to the protests, the additional blocking of WhatsApp, Instagram, Skype, Viber and Linkedin means that Iranians have fewer options for communicating, coordinating, sharing and accessing information. While Iran started blocking encrypted DNS services in 2020, the increased blocking of encrypted DNS endpoints in September 2022 means that circumventing Internet censorship will be harder. And the recent blocking of Google Play Store, Apple App Store, and browser extension repositories means that installing and updating apps and browser extensions (including circumvention tools) will be harder.

When comparing the recent Internet outages in Iran with the nationwide Internet shutdown in November 2019, we see that they differ in terms of impacted networks and duration. In 2019, multiple networks were impacted for 5 continuous days, whereas the recent outages mainly affected three mobile networks (primarily as part of “digital curfews”) over the span of several weeks.

Iran’s recent “digital curfews” are reminiscent of the nightly Internet outages (“digital curfews”) that Myanmar experienced for several months following the military coup in February 2021. In both cases, several independent network measurement data sets show that while Internet outages occurred almost like clockwork for specific hours each day, the blocking of major social media apps and circumvention tools remained ongoing. This shift towards targeted censorship (observed in both Myanmar and Iran) suggests that authorities may be attempting to minimize the cost of Internet outages (limiting them to specific networks and timings), while maximizing the political impact by maintaining the pattern of blockages for long periods.

Independent researchers can continue to monitor and investigate Internet shutdowns in Iran through publicly available datasets, such as OONI, IODA, Cloudflare Radar, Censored Planet, and M-Lab.

Annex: Methods

This study aims to investigate the breadth and extent of Internet shutdown events reported in Iran amid protests, following the death of Jhina (Mahsa) Amini on 16th September 2022.

For the purpose of this study, we have limited the analysis period to 16th September 2022 to 16th October 2022. This is the period immediately following Mahsa Amini’s death during which protests and censorship and shutdown events occurred. Several charts in this report provide longer date ranges (depending on the findings that they attempt to communicate), but the core findings of this analysis are between 16th September 2022 to 16th October 2022.

We analyze and compare relevant network measurement datasets that can help answer the following main questions:

To examine the above questions, we refer to the following datasets:

Each of the above datasets has its strengths and limitations, and they are designed to address different questions. They thus offer complementary insights when attempting to examine and corroborate Internet shutdown events.

In addition to network measurement data, ISOC also analyzed a variety of proxies for economic impact, as described below.

Technical Details of Blocking Analyses

To examine the blocking of apps and services, we refer to OONI and Censored Planet data. While both OONI and Censored Planet measure the blocking of websites, the measurement techniques and collection methods vary. OONI relies on volunteers in Iran and elsewhere to run OONI Probe to contribute measurements from local vantage points, while Censored Planet performs testing remotely from a centralized location.

OONI

OONI measures website blocking through its Web Connectivity experiment, which is designed to measure the accessibility of URLs by performing the following steps:

The above steps are automatically performed from both the local network of the user, and from a control vantage point. If the results from both networks are the same, the tested URL is annotated as accessible. If the results differ, the tested URL is annotated as anomalous, and the type of anomaly is further characterized depending on the reason that caused the failure (for example, if the TCP connection fails, the measurement is annotated as a TCP/IP anomaly).

Each Web Connectivity measurement provides further network information (such as information pertaining to TLS handshakes) that helps with evaluating whether an anomalous measurement presents signs of blocking. Based on its heuristics, OONI is often able to automatically confirm the blocking of websites. In recent years, Iranian ISPs have blocked websites by serving block pages and by returning IPs associated with censorship (which may have previously hosted block pages). By adding such fingerprints to their database, OONI has been able to automatically confirm the blocking of numerous websites in Iran. Moreover, the overall OONI measurement coverage in Iran is relatively high (in comparison to many other countries), increasing confidence in OONI findings.

Beyond website testing, the OONI Probe app also includes experiments for measuring the blocking of the WhatsApp, Facebook Messenger, Telegram, and Signal apps. OONI Probe also includes experiments for measuring the reachability of Psiphon, Tor, and Tor Snowflake, which are censorship circumvention tools. The methodology of each of these tests varies, as they measure different properties depending on the tool. Unlike Web Connectivity measurements, the measurements from all these other tests cannot be annotated as “confirmed blocked”, as OONI does not have heuristics for automatically detecting and confirming blocking. Instead, measurements pertaining to blocking are annotated as “anomalous”, and require data analysis to rule out false positives. This involves analyzing anomalous measurements in aggregate, comparing the overall volume of anomalies with the overall measurement count (on each network, for a specific date range), and evaluating whether the reasons that caused the anomalies are consistent. This analysis helps provide confidence levels regarding the likelihood of blocking.

Censored Planet

Censored Planet detects interference on HTTP(S) traffic by making use of publicly accessible web servers with consistent behavior as vantage points. Censored Planet first builds a template of a public web server’s typical response by requesting bogus domains that are not hosted on the server. After that requests are sent out with the HTTP “Host” header or TLS SNI extension set to a domain of interest. If there is a censor blocking the domain on the path between the measurement machine and the public web server, the measurement machine will receive a TCP RST, a blockpage, or experience a connection timeout that does not match the web server’s typical response.

Technical Details of Outage Analyses

To examine Internet outages, we refer to IODA, Cloudflare Radar, and Kentik data.

IODA

IODA measures connectivity of Internet infrastructure through three measurements: BGP, Active Probing, and Internet Pollution.

IODA has also integrated Google usage data, which is only available at the country level. These measurements are described further in the Google Transparency Report.

Cloudflare Radar

Based on its global network and the Internet traffic handled for millions of customers, Cloudflare aggregates this traffic data at both geographical (country/region/city) and network (ASN) levels. Internet outages are measured/inferred based on observed and sustained drops in traffic volume for a given geography or network, and we generally work to correlate these traffic changes with real-world events.

Kentik

Kentik is a popular cloud-based NetFlow analytics platform. Outage conclusions in this report are based on NetFlow from customers who have agreed to allow the use of their data in aggregate form. These customers include network service providers, content providers, and other types of major digital businesses whose use of the Internet is central to their business. Because this NetFlow data is from numerous sources, it represents a composite view of the Internet from multiple perspectives. NetFlow-based analysis is weakest when there is little or no traffic exchanged with a particular network or geography.

Technical Details of the Economic Impact Analysis

The economic information available about any country comes on many different time scales. For example, a common way to measure a country’s economic output is Gross Domestic Product (GDP). However, GDP is calculated on an annual basis, and a month-long period of shutdowns would likely not affect Iran’s total GDP in the short term. In addition, as GDP is designed to calculate macroeconomic changes, the effects of a shutdown could be too subtle to show up in a country-level measure. For example, the blocking of specific apps like WhatsApp would affect the ability of many Iranians to make transactions and/or interact with businesses, but it is unlikely that the effect of any of these could be identified easily in a GDP measure in the short term.

Instead, our goal is to collect as many economic indicators as possible that vary on the timeframe of days to weeks and that could show the effects of the shutdowns. None of these data points are causal, and any could be caused by myriad factors other than the shutdown (political instability, global markets in turmoil, low oil prices, etc.). We do, however, see some data points that suggest the shutdown has had an effect on economic activity in Iran, even as measuring the magnitude of that impact remains difficult.

As noted above, ISOC’s approach to measuring the impact of the shutdown in Iran relies on gathering many data points, none of which are causal, but paint a broad picture of how the shutdown may have affected the population of Iran’s economic activity. There are certainly many other ways to measure impact, but given how rapidly this shutdown evolved it would take further analysis to obtain useful data. Below are the sources of all of the data cited above.

Night-time lights data:

Suomi NPP / VIIRS Imagery from the NASA Worldview application (https://worldview.earthdata.nasa.gov), part of the NASA Earth Observing System Data and Information System (EOSDIS).

Financial markets data:

Mondo Visione Weekly Market Reviews for Tehran Stock Exchange (10 September to 12 October)

Trade data:

Imports and Exports data from UN COMTRADE Monitor: Link.

Cerdeiro, Komaromi, Liu and Saeed (2020); AIS data collected by MarineTraffic; available at UN COMTRADE Monitor.

Cerdeiro, D., Komáromi, A., Liu, Y., & Saeed, M. (2020). World Seaborne Trade in Real Time: A Proof of Concept for Building AIS-based Nowcasts from Scratch (No. 2020/057). International Monetary Fund.

Acknowledgement of limitations

This study includes several limitations. First, the date range of the analysis period is limited to 16th September 2022 to 16th October 2022. As a result, any Internet censorship and shutdown events that occurred before or after this date range are excluded from the findings of this study. Second, this study focuses on new Internet censorship events that emerged after 16th September 2022, and does not report on the many other ongoing blocks that have been in place in Iran for years.

Moreover, each dataset used as part of this study has its own limitations. For example, OONI data depends on when, where, and how often people in Iran choose to run OONI Probe. As a result, OONI measurement coverage in Iran varies from network to network and over time, and it also varies in terms of testing targets. This means that the findings may exclude censorship events that occurred on networks that were not tested, or if blocked services were not tested within the analysis period. Additionally, IODA limitations currently include limited visibility into cellular networks, inability to measure throttling, and challenges in the accurate geolocation of providers (ASes) that operate in multiple countries/sub-national regions. These limitations are part of ongoing research for improvement. Censored Planet’s vantage points are not fine-grained enough to measure every local instance of censorship, especially those applied very close to end-users, such as in schools or workplaces. Additionally, Censored Planet uses off-the-shelf geolocation databases that are known to sometimes be inaccurate.

Regarding the economic analysis, a general caveat on using nighttime lighting data to infer economic activity is that the data may be confounded by light-emitting phenomena (e.g., fires) that do not correlate with economic activity. Additionally, as noted above, causation is difficult to establish.

In general, the Internet is now a technically very complex network of networks which is key to organizing socio-economic and cultural activities of many different societies. Accordingly, the process of shutting down the communication processes of the Internet is equally complex, and the impacts pervasive. The participants of this report will continue working to improve the process of bringing transparency to Internet shutdowns and their impacts as rapidly and comprehensively as possible.