Rewterz Threat Alert – TA505 New Summer Campaign Introduces AndroMut Malware

Severity

Medium

Analysis Summary

Threat actors increasingly distributing downloaders, backdoors, information stealers, remote access trojans (RATs), and more as they abandoned ransomware as their primary payload. In November 2018, TA505, a prolific actor that has been at the forefront of this trend, began distributing a new backdoor we named “ServHelper”. ServHelper has two variants: one focused on remote desktop functions and a second that primarily functioned as a downloader. In June 2019, TA505 appears to have introduced yet another new downloader malware, AndroMut, which has some similarities in code and behavior to Andromeda, a long-established malware family. It has observed AndroMut download malware referred to as “FlawedAmmyy.” FlawedAmmyy is a full-featured RAT that was first observed in early 2016 and is based on the leaked source code of a legitimate shareware tool, Ammyy.

Impact

• Information theft
• Exposure of sensitive information

Indicators of Compromise

URLs

• http[:]//fakers[.]co[.]jp/[.]6[.]9_3[.][.]doc
• http[:]//greenthumbsup[.]jp/[.]6[.]9_746[.]38[.]doc
• http[:]//nagomi-753[.]jp/[.]6[.]9_784[.]9[.]doc
• http[:]//nagomi-753[.]jp/[.]6[.]9_8[.]77[.]doc
• http[:]//nanepashemet[.]com/[.]6[.]9_78[.]37[.]xls

Filename

• invoice-5601.doc
• invoice.xls

Malware Hash (MD5/SHA1/SH256)

• 3e3eb26211459eb2d8b52a2429a52e7e12d2145d7733823d7415663537a0b6ca
• 52f0aaff3654110e82586d21b07c8a3de23dc9efb3f4001daf412286282315c0
• 59af9102a921130fd1d120f6cee7fc7cdfc28292a7a4a8c24233126604aa9443
• 5eddc55c0c445baf2752d56229fa384b7e3f1c7e76b22f43e389c6a711aa713a
• 8621fa54946096ed38aee5cbcc068c0620416a05c17328a527673e808847850d
• 98b584b31457b21d0d48fcc78093439638e15dd1705e54182d9aa4ffad014c3a
• a905838db6e6617edd9d25baaaaee9c209381d456e809081977e27c3e0b15793
• bb5054f0ec4e6980f65fb9329a0b5acec1ed936053c3ef0938b5fa02a9daf7ee
• c4963dcf6b32459740f6a3d3b4d06d9dc06f15087ca01775956df36206543301
• d0aaf465a2569abbdcbafc049be1c1a643572f4ca185058833310435bfa53358
• eb3792fc83cd65823bc466e7253caf12064826b058230666d2ed51542ac59275
• f21039af47e7660bf8ef002dfcdb0c0f779210482ee1778ab7e7f51e8233e35c

Remediation

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