Severity

High

Analysis Summary

The initial infection vector used by the threat actor is a phishing email containing a malicious link. When pressed, the link downloads a supposedly legitimate zip file that is actually malicious. Sodinokibi zip files have a very low detection rate on VirusTotal, which signals that the majority of antivirus vendors do not flag the initial payload as malicious. Since the initial Sodinokibi payload is able to pass undetected, the first layer of defense for many organizations is immediately bypassed.

The zip file contains an obfuscated JavaScript file. When the user double clicks on the JavaScript file, WScript executes it.

The JavaScript file deobfuscates itself by rearranging characters from a list called eiculwo, which is located in the JavaScript file.

The variable vhtsxspmssj, located in the JavaScript file, is an obfuscated PowerShell script that will be deobfuscated by the attackers later on in the attack.

Impact

File encryption

Indicators of Compromise

Malware Hash (MD5/SHA1/SH256)

• 3e974b7347d347ae31c1b11c05a667e2
• b488bdeeaeda94a273e4746db0082841
• e402d34e8d0f14037769294a15060508
• b751d0d722d3c602bcc33be1d62b1ba2b0910e03
• 5dac89d5ecc2794b3fc084416a78c965c2be0d2a
• 2cc597d6bffda9ef6b42fed84f7a20f6f52c4756

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.