A new zero-day vulnerability that was disclosed on Twitter and GitHub two weeks ago has already been weaponized for use in the wild.

As reported by We Live Security, the tweet posted on Aug. 27 linked to a GitHub repository containing proof-of-concept code for the exploit, which affects Windows operating systems 7 through 10, along with its source code. The tweet was subsequently deleted, but a group known as PowerPool used the link to create its own version of this zero-day attack and infect computers in Chile, Germany, India, the Philippines, Poland, Russia, the U.K., the U.S. and Ukraine.

By leveraging a flaw in the advanced local procedure call (ALPC) process, specifically the SchRpcSetSecurity application programming interface (API) function, attackers can grant restricted users the power to view and change the contents of write-protected files. PowerPool’s developers have been using a combination of typical spear phishing emails and spamming symbolic link (.slk) files that open Microsoft Excel and then execute PowerShell scripts.

Why Leaked Source Code Poses a Threat

Along with the quick uptake of this threat vector as part of PowerPool’s tool set and the ever-present use of phishing emails, companies should also be aware of the risk presented by the dissemination of source code. Because the GitHub link contained both a compiled version of the exploit and its source code, threat actors can quickly modify and recompile the zero-day vulnerability to streamline its functionality, integrate it into a larger malware package and evade detection.

Security teams should also take note of PowerPool’s use of multiple backdoors. The first-stage backdoor conducts basic reconnaissance, such as collecting proxy information and screenshotting the victim’s display, then sending this data back to the command-and-control (C&C) server. A second-stage backdoor is then installed on devices that hold more data, allowing malicious actors to execute commands, kill processes, upload and download files, and list folders. In addition, lateral movement tools — such as PowerDump and PowerSploit — are installed along with second-stage backdoors.

How Can Companies Zero In on Zero-Day Flaws?

Since “zero-day flaws are just vulnerabilities for which there is no patch,” according to IBM X-Force threat intelligence expert Michelle Alvarez, IT asset management (ITAM) is crucial to handling this type of exploit. While it’s impossible to predict the occurrence of zero-day threats, effective management of IT assets makes it easier to identify potential risk vectors and critical points of entry.

Cybersecurity adviser Michael Melore, meanwhile, recommends developing “cybersecurity muscle memory” by creating and regularly testing incident response plans (IRPs) for zero-day attacks and other threats. That way, even if unexpected disclosures occur, security professionals are ready to react.

Source: We Live Security

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