The FBI has warned the public, private sector, and the world about the “victimization of US-based businesses”, as cyberattacks involving remote IT workers from North Korea are on the rise. It has noticed North Korean IT workers gaining illegal access to systems to steal confidential data and launch other cyber-crime operations.
In an FBI announcement reported by Forbes, it was disclosed that “victims have seen proprietary data and code held to ransom,” and “the copying of corporate code repositories to attacker user profiles and personal cloud accounts.” Additionally, the attackers have also “attempted harvesting of company credentials and session cookies for further compromise opportunities.”
Law enforcement and intelligence agencies like the FBI and NSA (National Security Agency) have advised the principle of least privilege, to “only allow designated administrator accounts to be used for administrative purposes.” The aim is to limit the administrative rights available to Mac and Windows users to ensure security.
The principle of least privilege gives admin account access to only selected people, and nobody else. The method ensures company employees only have access to particular resources needed to get the job done, not admin rights. For instance, the user account completes day-to-day needs, whereas for something critical, like software installation, the systems will ask for admin credentials.
Wikipedia is one great example of using this technique, it has user accounts for making backups that don’t need to install software and only have rights for running backups and related applications.
The FBI suggests businesses disable local administrator accounts and restrict privileges for installing remote desktop apps, keeping an eye out for any unusual network traffic. It has warned organizations to remember that “North Korean IT workers often have multiple logins into one account in a short period of time,” coming from various IP addresses linked with different countries.
The agency has also advised HRs, development teams, and hiring managers to focus “on changes in address or payment platforms during the onboarding process.”
A North Korean cybercriminal group, Andariel, has been found using a stealthy hacking technique called RID hijacking to gain full control over Windows systems. This method allows attackers to manipulate a computer’s security settings, turning a low-privilege user account into an administrator account and granting them hidden control over the system.
Windows assigns each user account a Security Identifier (SID), which includes a Relative Identifier (RID) that defines the account’s access level. Key RIDs include:
Hackers exploit this system by modifying the RID of a normal user account to match that of an administrator. Since Windows determines permissions based on RID values, the system unknowingly grants higher-level access to what appears to be a low-privilege account. However, this attack requires deep access to the system’s core security files, specifically the Security Account Manager (SAM) registry, where user login details are stored.
Researchers from AhnLab Security Intelligence Center (ASEC) have linked these attacks to Andariel, a North Korean hacking group that is part of Lazarus, a well-known state-sponsored cybercrime organization. Andariel typically gains initial access by exploiting software vulnerabilities or tricking users into downloading malware. Once inside, they use hacking tools like PsExec and JuicyPotato to obtain SYSTEM-level privileges, the highest level of access on a Windows machine.
However, SYSTEM-level access has limitations, such as the inability to log in remotely, lack of persistence after a system restart, and high visibility to security systems. To overcome these, Andariel creates a hidden user account using the Windows "net user" command, adding a "$" symbol at the end of the username to make it invisible in regular user lists. They then modify its RID to that of an administrator, granting it full control over the system while remaining undetected.
To protect against RID hijacking, organizations and IT administrators can take the following steps:
RID hijacking has been known since 2018, when cybersecurity researchers first demonstrated it as a way to maintain persistent access on Windows systems. However, its recent use by North Korean state-sponsored hackers highlights the growing sophistication of cyberattacks. By making small, undetectable changes to Windows user settings, hackers can silently maintain control over a compromised system, making it much harder for security teams to remove them.
The use of RID hijacking by North Korean hackers underscores the importance of proactive cybersecurity measures. Organizations must monitor user accounts, detect hidden activity, and secure critical system files to defend against such stealthy attacks. By staying vigilant and implementing robust security practices, businesses can better protect their systems from advanced threats like RID hijacking.