The North Korean threat actor known as ScarCruft has recently exploited a Windows zero-day vulnerability, CVE-2024-38178, to distribute the RokRAT malware. This particular security flaw, rated with a CVSS score of 7.5, is a memory corruption issue in the Windows Scripting Engine that allows for remote code execution when using Microsoft Edge in Internet Explorer Mode. Although Microsoft patched this vulnerability as part of its August 2024 updates, ScarCruft had already begun targeting users through malicious advertisements prior to the patch, taking advantage of this significant security weakness.
The attack, referred to as “Operation Code on Toast,” was identified by the AhnLab Security Intelligence Center (ASEC) and the National Cyber Security Center (NCSC) of South Korea. In this operation, ScarCruft compromised the server of a domestic advertising agency, injecting malicious exploit code into “toast” ads—pop-up notifications that typically appear in the lower-right corner of users’ screens. These ads, often bundled with various free software, served as a delivery mechanism for the exploit. When users interacted with these ads, the vulnerability was triggered, allowing the attackers to gain remote access to the infected systems.
Once inside, the RokRAT malware facilitated a range of malicious activities for ScarCruft, including file enumeration, command execution, and data exfiltration from popular applications such as KakaoTalk and WeChat. Notably, RokRAT utilizes legitimate cloud services like Dropbox, Google Cloud, and Yandex Cloud as its command-and-control infrastructure. This tactic allows the malware to blend in with regular network traffic, making it more challenging for security teams to detect its malicious activities. By leveraging such cloud services, ScarCruft enhances the stealth of its operations while executing commands from a remote server.
This incident underscores a broader trend of ScarCruft exploiting vulnerabilities in legacy browser components to conduct cyberattacks. In recent years, the group has been attributed with leveraging other critical security flaws, such as CVE-2020-1380 and CVE-2022-41128, to deliver follow-on malware. As the technological capabilities of North Korean hacking organizations continue to advance, cybersecurity experts emphasize the importance of maintaining updated operating systems and software. To protect against these evolving threats, users are urged to regularly install security patches and adopt robust cybersecurity practices to mitigate risks associated with such vulnerabilities. By being proactive in their security measures, organizations can better safeguard their systems from sophisticated attacks like those orchestrated by ScarCruft.
