Menace hunters have shed mild on a “subtle and evolving malware toolkit” known as Ragnar Loader that is utilized by numerous cybercrime and ransomware teams like Ragnar Locker (aka Monstrous Mantis), FIN7, FIN8, and Ruthless Mantis (ex-REvil).
“Ragnar Loader performs a key function in protecting entry to compromised programs, serving to attackers keep in networks for long-term operations,” Swiss cybersecurity firm PRODAFT stated in an announcement shared with The Hacker Information.
“Whereas it is linked to the Ragnar Locker group, it is unclear in the event that they personal it or simply lease it out to others. What we do know is that its builders are consistently including new options, making it extra modular and more durable to detect.”
Ragnar Loader, additionally known as Sardonic, was first documented by Bitdefender in August 2021 in reference to an unsuccessful assault carried out by FIN8 aimed toward an unnamed monetary establishment situated within the U.S. It is stated to have been put to make use of since 2020.
Then in July 2023, Broadcom-owned Symantec revealed FIN8’s use of an up to date model of the backdoor to ship the now-defunct BlackCat ransomware.
The core performance of Ragnar Loader is its skill to ascertain long-term footholds inside focused environments, whereas using an arsenal of strategies to sidestep detection and guarantee operational resilience.
“The malware makes use of PowerShell-based payloads for execution, incorporates robust encryption and encoding strategies (together with RC4 and Base64) to hide its operations, and employs subtle course of injection methods to ascertain and keep stealthy management over compromised programs,” PRODAFT famous.
“These options collectively improve its skill to evade detection and persist inside focused environments.”
The malware is obtainable to associates within the type of an archive file bundle containing a number of elements to facilitate reverse shell, native privilege escalation, and distant desktop entry. It is also designed to ascertain communications with the risk actor, permitting them to remotely management the contaminated system by way of a command-and-control (C2) panel.
Sometimes executed on sufferer programs utilizing PowerShell, Ragnar Loader integrates a bevy of anti-analysis strategies to withstand detection and obscure management stream logic.
Moreover, it options the power to conduct numerous backdoor operations by working DLL plugins and shellcode, in addition to studying and exfiltrating the contents of arbitrary recordsdata. To allow lateral motion inside a community, it makes use of one other PowerShell-based pivoting file.
One other vital part is a Linux executable ELF file named “bc” that is designed to facilitate distant connections, allowing the adversary to launch and execute command-line directions immediately on the compromised system.
PRODAFT instructed the publication that “bc” is much like the BackConnect modules current in different recognized malware households like QakBot and IcedID that allow distant interplay with the sufferer’s system. “This can be a frequent approach amongst cybercriminals, particularly for focusing on enterprise victims, as their units are sometimes network-isolated,” it stated.
“It employs superior obfuscation, encryption, and anti-analysis strategies, together with PowerShell-based payloads, RC4 and Base64 decryption routines, dynamic course of injection, token manipulation, and lateral motion capabilities,” the corporate added. “These options exemplify the rising complexity and flexibility of recent ransomware ecosystems.”
