This researcher just beat ransomware gangs at their own game

A security researcher has discovered key flaws pertaining to popular ransomware and malware — a state of affairs that could lead to their creators entirely rethinking the approach to infiltrate potential victims.

Currently, among the most active ransomware-based groups are the likes of Conti, REvil, Black Basta, LockBit, and AvosLocker. However, as reported by Bleeping Computer, the malware developed by these cyber gangs has been found to come with crucial security vulnerabilities.

These defects could very well prove to be a damaging revelation for the aforementioned groups — ultimately, such security holes can be targeted in order to prevent what the majority of ransomware is created for; the encryption of files contained within a system.

A security researcher, hyp3rlinx, who specializes in malware vulnerability research, examined the malware strains belonging to the leading ransomware groups. Interestingly, he said the samples were exposed to dynamic link library (DLL) hijacking, which is a method traditionally used by attackers themselves that targets programs via malicious code.

“DLL hijacking works on Windows systems only and exploits the way applications search for and load in memory the Dynamic Link Library (DLL) files they need,” Bleeping Computer explains. “A program with insufficient checks can load a DLL from a path outside its directory, elevating privileges or executing unwanted code.”

The exploits associated with the ransomware samples that were inspected by hyp3rlinx — all of which are derived from Conti, REvil, LockBit, Black Basta, LockiLocker, and AvosLocker — authorize code that can essentially “control and terminate the malware pre-encryption.”

Due to the discovery of these flaws, hyp3rlinx was able to design exploit code that is assembled into a DLL. From here, that code is assigned a certain name, thereby effectively tricking the malicious code into detecting it as its own. The final process involves loading said code so that it commences the process of encrypting the data.

Conveniently, the security researcher uploaded a video that shows how a DLL hijacking vulnerability is used (by ransomware group REvil) to put an end to the malware attack before it can even begin.

The significance of the discovery of these exploits

As highlighted by Bleeping Computer, a typical area of a computer targeted by ransomware is a network location that can house sensitive data. Therefore, hyp3rlinx asserts that after the DLL exploit is loaded by placing that DLL in certain folders, the ransomware process should theoretically be stopped before it can inflict damage.

Malware is capable of evading security mitigation processes, but hyp3rlinx stresses that malicious code is completely ineffective when it faces DLLs.

That said, whether the researcher’s investigation results in long-lasting changes in preventing or at least reducing the impact of ransomware and malware attacks is another question entirely.

“If the samples are new, it is likely that the exploit will work only for a short time because ransomware gangs are quick to fix bugs, especially when they hit the public space,” Bleeping Computer said. “Even if these findings prove to be viable for a while longer, companies targeted by ransomware gangs still run the risk of having important files stolen and leaked, as exfiltration to pressure the victim into paying a ransom is part of this threat actor’s modus operandi.”

Still, the cybersecurity website added that hyp3rlinx’s exploits “could prove useful at least to prevent operational disruption, which can cause significant damage.”

As such, although it’s likely to be patched soon by ransomware groups in the immediate future, finding these exploits is an encouraging first step toward impacting the development and distribution of dangerous code. It may also lead to more advanced mitigation methods to prevent attacks.

Ransomware groups do not consist of your average hackers. Creating and spreading effective malware is a sophisticated task in and of itself, and the financial windfall from a successful attack can generate hundreds of millions of dollars for the perpetrators. A considerable portion of those ill-gotten gains is extracted from innocent individuals.

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