Network data show that Wikipedia servers have become intermittently unavailable as of approximately 6:00 p.m. UTC Friday 6 September 2019. Measurements show the disruptions are not related to filtering and have global impact with a focal point around Europe.

At 1:30 a.m. UTC, Saturday, the attack extended to a near-total outage in the United States and much of the world, continuing up until 2:40 a.m. UTC as of when access is, for the time being, restored:

Update: Wikipedia is back online as of 02:40 UTC; a #DDoS attack variously targeting @Wikimedia infrastructure in the US and Europe has now caused ~9 hours of intermittent global outages #WikipediaDown 📉📈 📰 https://t.co/OyuN6MwxIH pic.twitter.com/Lnq2DkYr6h — NetBlocks.org (@netblocks) September 7, 2019

Data indicate that the attack was initially staged in two phases, with the first briefly causing high latencies in the Americas from 6:00 p.m. UTC, and the second resulting in more severe outages across Western, Central and Eastern Europe, with disruptions also affecting the Middle East and South Asia.

Confirmed: Wikipedia is experiencing intermittent global outages for the second time today; disruptions affecting all language editions of the online encyclopedia began 6:00 p.m. UTC; incident ongoing 📉 📰 https://t.co/OyuN6MwxIH pic.twitter.com/ov83LExCs5 — NetBlocks.org (@netblocks) September 6, 2019

At 9 p.m. UTC Wikimedia Germany reported a “massive and very broad” DDoS (Distributed Denial of Service) attack on Wikimedia Foundation servers, explaining that Wikipedia and sister projects are temporarily unavailable:

Die Wikimedia-Server der @Wikimedia Foundation, auf denen auch Wikipedia gehostet wird, werden gerade durch einen massiven und sehr breit angelegten DDoS-Angriff lahm gelegt. #Wikipedia und ihre Schwesterprojekte sind daher vorübergehend nicht erreichbar. Sorry! https://t.co/fAemzOGhfm — WikimediaDeutschland (@WikimediaDE) September 6, 2019

The Wikimedia Foundation has measures in place to mitigate attacks orchestrated by disgruntled users and governments demanding editorial changes or takedowns of unfavourable articles.

A total global Wikipedia outage was identified on 15 May 2019, and the site often faces disruptions of lower magnitude although outages are rarely protracted:

Confirmed: Wikipedia is experiencing global outages as of 12:25 p.m. UTC; network data confirms incident not related to internet filtering or censorship 📉https://t.co/wIznkhkZ1n pic.twitter.com/reKkI2Pxje — NetBlocks.org (@netblocks) May 15, 2019

The motivation and origin of the current attack have not yet been established. The popular online encyclopedia has been totally blocked in Turkey since 2017, is varyingly restricted in China, and was briefly filtered in Venezuela in January 2019. DDoS attacks are distinct from instances of state filtering or blocking, because they have broader international impact but typically last for short periods.

NetBlocks is partnered with Wikimedia Norway to support access to knowledge globally, monitoring access to over 200 Wikipedia language editions around the world in real-time.

Wikimedia Norge and @netblocks join forces at to work on access to knowledge in the face of increasing government censorship: https://t.co/rC10ddQPen #wemissturkey #keepiton #OsloFF #Wikipedia — Wikimedia Norge (@WikimediaNorge) May 30, 2018

Methodology

Internet performance and service reachability are determined via NetBlocks web probe privacy-preserving analytics. Each measurement consists of latency round trip time, outage type and autonomous system number aggregated in real-time to assess service availability and latency in a given country. Network providers and locations enumerated as vantage point pairs. The root cause of a service outage may be additionally corroborated by means of traffic analysis and manual testing as detailed in the report.

Internet performance and service reachability are determined via NetBlocks web probe privacy-preserving analytics. Each measurement consists of latency round trip time, outage type and autonomous system number aggregated in real-time to assess service availability and latency in a given country. Network providers and locations enumerated as vantage point pairs. The root cause of a service outage may be additionally corroborated by means of traffic analysis and manual testing as detailed in the report.

NetBlocks is a civil society group working at the intersection of digital rights, cyber-security and internet governance. Independent and non-partisan, NetBlocks strives for an open and inclusive digital future for all.