Rewterz Threat Alert – Kassino Campaign Spreading Agent Tesla via Phishing Emails

Severity

Medium

Analysis Summary

A new campaign dubbed “Kassino” spreading Agent Tesla malware, a known information stealing Trojan. Agent Tesla monitors and collects the victim’s keyboard inputs, system clipboard, screen shots of the victim’s screen, as well as collects credentials of a variety of installed software. Initial infection starts with a spear phishing email:

Attached to this email is a zip file named “Averda7803.zip” and contains an executable file “jack.exe” which is the final stage malware. Once directly executed on the machine, the malware installs persistence mechanisms by executing VBS scripts via the RunOnce registry key. It then implements hooks into all the major browsers for the purpose of credential harvesting and stealing. One unique aspect of the malware is that it uses SMTP for command and control and exfiltration of data.

Impact

• Information theft
• Exposure of sensitive information

Indicators of Compromise

Filename

• Averda7803.zip
• jack.exe
• filename.exe
• filename.vbs

Malware Hash (MD5/SHA1/SH256)

• 203AA57D68DDFA6C0E644D9E1CBB24DC
• 4fafeeaf52bc073bbc56bed994d99b43
• 3558065e64d9b53381250c357a4fabf392488e54

Remediation

• Block all threat indicators at your respective controls.
• Always be suspicious about emails sent by unknown senders.
• Never click on the link/attachments sent by unknown senders.