Menace hunters have shed light on a “refined and evolving malware toolkit” known as Ragnar Loader that is utilized by varied cybercrime and ransomware teams like Ragnar Locker (aka Monstrous Mantis), FIN7, FIN8, and Ruthless Mantis (ex-REvil).
“Ragnar Loader performs a key function in preserving entry to compromised programs, serving to attackers keep in networks for long-term operations,” Swiss cybersecurity firm PRODAFT stated in a press release 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 hire it out to others. What we do know is that its builders are consistently including new options, making it extra modular and tougher 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 positioned 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 potential to ascertain long-term footholds inside focused environments, whereas using an arsenal of methods 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 refined course of injection methods to ascertain and keep stealthy management over compromised programs,” PRODAFT famous.
“These options collectively improve its potential to evade detection and persist inside focused environments.”
The malware is obtainable to associates within the type of an archive file package deal containing a number of parts 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 a command-and-control (C2) panel.
Usually executed on sufferer programs utilizing PowerShell, Ragnar Loader integrates a bevy of anti-analysis methods to withstand detection and obscure management circulate logic.
Moreover, it options the flexibility to conduct varied backdoor operations by working DLL plugins and shellcode, in addition to studying and exfiltrating the contents of arbitrary information. To allow lateral motion inside a community, it makes use of one other PowerShell-based pivoting file.
One other important part is a Linux executable ELF file named bc that is designed to facilitate distant connections, allowing the adversary to launch an and execute command-line directions straight on the compromised system.
“It employs superior obfuscation, encryption, and anti-analysis methods, together with PowerShell-based payloads, RC4 and Base64 decryption routines, dynamic course of injection, token manipulation, and lateral motion capabilities,” PRODAFT stated. “These options exemplify the rising complexity and flexibility of contemporary ransomware ecosystems.”
