256 websites that are mostly porn-related, suddenly became inaccessible. While their servers were showing no problems whatsoever, they couldn't be accessed from many countries. When users type the URL of the affected websites, they were greeted with a blank page.
The culprit came from Iran. The nation that lies deep in the Middle East, began blocking not just websites in order to censor adult-related contents for its nation's consumers. It began to block the basic mechanism of the web itself.
Iran's biggest ISP, The Telecommunication Company of Iran (TCI), had announced fraudulent routes for each of the 256 sites. The resulting outage didn't affect the entire web, but anyone close enough to be tempted by the phony routes was affected.
The problem is because Iran which has a strict rule for internal censorship, is also the pivotal transit data throughout the region.
Users of India's Bharti Airtel, Russia's RETN, Indonesia's Telkom and Hong Kong's Hutchison were all affected. They are all major ISPs for their region.
The TCI used a method called BGP hijacking, an attack that exploits a long-standing vulnerability in the architecture of the web. What the method does is to takeover groups of IP addresses by corrupting the internet's routing tables, rerouting the networks to other IP addresses.
After 28 hours, the issue started to resolve itself, with most of the networks affected having revoked the phony routes. However, the reroutes still affect Iran.
Questions started circulating as Iran typically uses more reliable means to block internet contents. From ISP-level blocks to nationwide packet inspections, for example. The BGP method is typically not the mechanism that is used for domestic censorship, largely due to the fact that it's extremely noisy, easily mitigated against, and has the potential to spread past a country's borders.
