The US National Security Agency (NSA) today issued a warning about a new wave of cyber attacks against email servers. The attacks were carried out by one of the most advanced units espionageof Russia.
The NSA reports that members of Unit 74455 of the GRU Main Center for Special Technologies, a division of Russia's military intelligence service, attacked email servers running Exim mail transfer agent (MTA).
The group also known as "Sandworm", attacks Exim servers από τον Αύγουστο του 2019 εκμεταλλευόμενη μια κρίσιμη ευπάθεια (CVE-2019-10149), αναφέρει η NSA σε μια ειδοποίηση security [PDF] announced today.
"When Sandworm exploits CVE-2019-10149, the victim's system downloads and runs a shell script from a controlled domain by Sandworm," the NSA said.
This shell script I will:
- Add privileged users
- Disable network security settings
- Update SSH settings to allow remote access
- Run an additional script to allow further exploits
The NSA now warns private and government agencies to update Exim servers to version 4.93 and look for signs of breach. Violations are listed in the PDF issued by the NSA.
The Sandworm group has been active since the mid-2000s and is believed to be the hacker group that developed the malware BlackEnergy which caused a blackout in Ukraine in December 2015. In December 2016 and the team developed the famous ransomware NotPetya which caused billions of dollars in losses to companies around the world.
Vulnerability CVE-2019-10149 was unveiled in June 2019 and has the code name "Return of the WIZard".
Within a week of its revelation, various hacking groups began using it. Two weeks later, Microsoft also issued a warning at the time, warning Azure customers.
Almost half of all Internet email servers run on Exim. According to statistics as of May 1, 2020, only half of these Exim servers have been updated to version 4.93 or later, leaving a large number of systems vulnerable to attack.
