A new wave of infamous credential stealer malware “Separ” infects organizations through living off the land attack methods.
In this campaign, threat actors leverage new file hosting service and a legitimate FTP client to upload the exfiltrate and to store data.
According to DeepInstinct, the activity still continues and the data extracted are stored on a daily basis to the hosting service.
The campaign targeted a number of companies in South East Asia and the Middle East, some targets in North America. The attack targeting business organizations with fake documents appear to be for quotations, shipments, and equipment specifications.
Infection Chain – Separ
The infection starts with a phishing email that contains malicious attachments, mostly decoy PDF document, present in a self-extracting archive. the archive contains a VB Script(adobel.vbs), two batch scripts(adob01.bat, adob02.bat), and four executable files(adobepdf.exe, adobepdf2.exe, ancp.exe, and Areada.exe).
Files present in the archive appears to be related with Adobe, when the user clicks on the PDF attachment with the Email, then the VB Script will be executed.
The VB script calls batch script(adob01[.]bat) which copies several files and executes the second batch file (adob02[.]bat) that performs various malicious functions.
According to DeepInstinct analysis, it performs the following functions.
- Opens an empty decoy jpg, which hides additional command windows.
- Changes firewall settings.
- Saves ipconfig /all results into a file.
- Steals credentials.
- Renames the extracted passwords and upload via FTP
- Turns computer to sleep, once it runs second batch script once sleep completed
Attackers used haven’t used any obfuscation or evasion techniques and the spear uses various legitimate tools that include xcopy.exe, attrib.exe, sleep.exe (renamed Areada.exe), and ancp.exe.
Extracted details are stored in an FTP server belong to a well-known hosting provider( freehostia.com) using an FTP client ancp.exe.
The growth in the number of victims claimed by this malware shows that simple attacks can be very effective, DeepInstinct said.