Identified by Proofpoint as the threat actor behind the Contact Forms campaign, TA578 also appears to be pushing ISO files for Bumblebee malware through thread-hijacked emails. These threat-hijacked emails either have links to storage.googleapis.com URLs similar to those used in the Contact Forms campaign, or they have password-protected zip attachments. Either method delivers an ISO file containing files to install Bumblebee malware.
Today's diary compares two examples of ISO files for Bumblebee malware from Monday 2022-05-09 that appear to be from TA578.
INFECTION CHAIN COMPARISON: LINK TO 'DOCUMENT' DOWNLOAD PAGE:
INFECTION CHAIN COMPARISON: PASSWORD-PROTECTED ZIP ATTACHMENT:
ISO FILE COMPARISON:
ISO CONTENT COMPARISON:
Note: Both of the above ramest.dll files have the same import hash (imphash) of 66356a654249c4824378b1a70e7cc1e5
SIMILARITIES TO CONTACT FORMS CAMPAIGN:
TA578 'document' download pages are similar to 'Stolen Images Evidence' pages used for the Contact Forms campaign. Both are hosted on storage.googleapis.com pages with appspot.com in the URL. Both generate traffic to a malicious URL ending in logo.jpg that returns script with base64 text used to generate a malicious ISO file for download.
The following are 4 examples of URLs generated by 'document' download pages for malicious ISO files in May 2022:
The following are 4 examples of URLs generated by 'Stolen Images Evidence' pages for malicious ISO files in May 2022:
As seen above, 'Stolen Images Evidence' pages generate URLs ending in /images/logo.jpg, while 'document' download pages generate URLs ending in /img/logo.jpg.
URLs hosted on storage.googleapis.com for 'Stolen Images Evidence' pages end with ?l= or ?h= or similar strings ollowed by a numeric value. For example, hxxps://storage.googleapis[.]com/oieqeh1cxwnd81.appspot.com/bl/file/sh/0/fWpa4HT4ck6v6.html?l=827470894993112750 is a URL for a recent 'Stolen Images Evidence' page.
URLs hosted on storage.googleapis.com for 'document' download pages end in .html. For example: hxxps://storage.googleapis[.]com/pz3ksj5t45tg4t.appspot.com/q/pub/file/0/filejBWdkst6Ua3s.html is a URL for a recent 'document' download page.
The Contact Forms campaign switches between pushing ISO files for Bumblebee malware, or pushing ISO files for IcedID (Bokbot) malware, and I've seen both during the same week. Since February 2022, TA578 has been noted pushing both families of malware. And in recent weeks, TA578 has been using thread-hijacked emails to distribute ISO files for Bumblebee malware. TA578 might also distribute IcedID using the same type of thread-hijacked messages.
While the malware may be different, I occasionally find Cobalt Strike from either Bumblebee or IcedID when testing samples in Active Directory (AD) environments. Cobalt Strike can lead to ransomware or other malicious activity.
If TA578 activity is caught and stopped in its early stages, potential victims might avoid more serious harm.
May 11th 2022
May 11th 2022
2 weeks ago