STAC5777 Attack Chain: A Complex Malware Campaign

Stages of the Attack Chain

The STAC5777 attack chain was more involved, with more hands-on-keyboard hacking and commands. During the first stage, the attacker used the browser to download two .dat files, which they then combined into an archive called pack.zip.

The archive contained multiple files, including a legitimate executable called OneDriveStandaloneUpdater.exe, two .dll files from the OpenSSL Toolkit project, an unknown winhttp.dll, and a file called settingsbackup.dat. The archive and files were unpacked in a folder called OneDriveUpdate under the Windows AppData directory.

Unpacking the Archive

The legitimate executable, OneDriveStandaloneUpdater.exe, was responsible for unpacking the archive and files. The files were extracted to a folder called OneDriveUpdate under the Windows AppData directory.

Malware Capabilities

The winhttp.dll file was a backdoor that was automatically sideloaded by the legitimate OneDrive executable. This file was capable of gathering system information, including configuration details, the name of the current user, and recording keystrokes.

The researchers believe that the winhttp.dll was meant to decrypt the settingsbackup.dat and execute it as a second-stage payload, but they did not manage to analyze this file. The malware’s capabilities allowed it to exfiltrate sensitive information, making it a significant threat to system security.

Conclusion

The STAC5777 attack chain was a complex and sophisticated malware campaign that utilized multiple stages and techniques to compromise systems. The malware’s ability to gather system information and record keystrokes makes it a significant threat to system security. It is essential for organizations to be aware of these types of attacks and take proactive measures to protect themselves.

Frequently Asked Questions

What is the STAC5777 Attack Chain?

The STAC5777 attack chain is a complex malware campaign that involves multiple stages and techniques to compromise systems.

What are the Stages of the Attack Chain?

The STAC5777 attack chain involves the following stages:

• Stage 1: Downloading and combining .dat files
• Stage 2: Unpacking the archive and files
• Stage 3: Execution of the malware payload

What is the Purpose of the Malware?

The malware is designed to gather system information, record keystrokes, and potentially decrypt and execute a second-stage payload.

How Can I Protect My System from This Attack Chain?

It is essential to keep software up-to-date, use strong passwords, and implement robust security measures to prevent the exploitation of vulnerabilities.