Corero Network Security has disclosed a "kill switch" for the Memcached vulnerability to national security agencies and shared new evidence indicating the flaw is more dangerous than previously believed. For the first time, threat actors have been exploiting unsecured Memcached servers to launch distributed denial-of-service (DDoS) attacks on target businesses.
Memcached is an open-source memory caching system that stores data in RAM to accelerate access times. It was not built for Internet access; users don't have to authenticate. This exploit lets attackers create spoof requests and boost attacks up to 50,000 times.
The attacks, which hit businesses including GitHub, started in late February. German DDoS mitigation service provider Link11 was among the first to report the new activity, which included UDP attacks using Memcached servers to spread. Link11 found 5,000 vulnerable Memcached servers on the public internet.
Corero researchers have discovered that any exposed Memcached server that can be leveraged for a DDoS attack can also be tricked into sharing user data it has cached from its local network or host. Because Memcached servers don't require authentication, anything added to a vulnerable server can be stolen. Attackers can also modify data and reinsert it in the cache without owners' knowledge.
The "kill switch" sends a command back to the attackers' server to suppress the current DDoS exploitation. This invalidates the cache of a vulnerable server, including attackers' potentially malicious payload. It has been effectively tested on live attacking servers, Corero reports.
Read more details here.
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