Stealthy Linux rootkit found in the wild after going undetected for 2 years

Stealthy and multifunctional Linux malware that has been infecting telecommunications companies went largely unnoticed for two years until being documented for the first time by researchers on Thursday.

Researchers from security firm Group-IB have named the remote access trojan “Krasue,” after a nocturnal spirit depicted in Southeast Asian folklore “floating in mid-air, with no torso, just her intestines hanging from below her chin.” The researchers chose the name because evidence to date shows it almost exclusively targets victims in Thailand and “poses a severe risk to critical systems and sensitive data given that it is able to grant attackers remote access to the targeted network.

During the initialization phase, the rootkit conceals its own presence. It then proceeds to hook the kill() syscall, network-related functions, and file listing operations, thereby obscuring its activities and evading detection.

The researchers have so far been unable to determine precisely how Krasue gets installed. Possible infection vectors include through vulnerability exploitation, credential-stealing or -guessing attacks, or by unwittingly being installed as trojan stashed in an installation file or update masquerading as legitimate software.