Andromeda/Gamarue bots are routinely used as backdoors to infected systems and can also be vectors for downloading different malicious payloads.
Over the last few weeks we noticed the resurgence of a particular spam campaign that is distributing Andromeda/Gamarue to Italian domains, with a couple of bursts in the last 20 days but also going back to April and May 2015.
Our systems collected more than 4000 unique emails with malicious attachments that can be linked to Andromeda with an ultimate goal of distributing two particular families of financial malware. Spam relays linked to this campaign are primarily located in Europe with a strong focus on Spain and Italy.
The attachments (ZIP archives) have been crafted using names that resemble standard Italian business documents, but actually they are executable files compromising the system. As previously reported, the malicious executable creates a new msiexec.exe process and injects code into it, then it joins the Andromeda botnet by connecing to the C&C 93.115.38[.]134 using an RC4-encoded JSON.
In the second stage of infection, we have observed the download of one or two different payloads: Citadel (“ssdc32716372” gang) or Gozi/Ursnif (a recent variant, see here and here). In the recent past, other Andromeda botnets have been detected, one of them dropping Lethic malware instead of infostealers.
On June, 24th we also identified a different sample having the same behaviour but targeting German users. That sample is using a different Command and Control server 5.9.253[.]153.
Some IOCs we have identified so far:
MD5 hashes
0290d35ab5caad08a51034bb09c4d023 21435848d62a094ecd30b8128fd6209b 238d4107ede2bc48b3372a62bfd8d5cd 28e01a0e29155e5b993dff915acea976 2ec3bd331846e717a80efb7c33682c6f 30441510bcc4123dd0f0cf211bdc104b 3d3188e83f64ed6ae2a14896f9a1eade 4f011d0d9abac35c7d1125b754730a43 589632bd743554004afc24ecc0b13834 5c59eeb9b1762c4af5c89226262b6327 7fa569b2ccd73da52a181918367d986e 879f701d990e54acf14614090cdd255d 8c4105ebcd57be6de710d0094efbc32a 8e0f37f2d36aada0ba87f5e66a3c27ff a693f356384bbf61258688563ea843b9 af911be206423bf440ea9d4df075a632 b5c36f29948fb76c31fb045652abcac2 dabac137f4e1a7a33072c6c08f7abe55 ef947b2c2c36b76a0ceb87880654206c f2bed8f637dfd4a07850a699a983a311
Attachment names
349-fattura-dal-13-05-2015-creata-automaticamente-sistema-automatica.exe DSC_0101_0111[jpg].jpeg-.exe FATT. 130-2015 SRL noleggio_pdf_.exe FT. 118 - 2015 srl noleggio _docx_.doc.exe MMS_Email_N_8900277.jpeg_.exe booking_hotel_confirmation.pdf_.exe fatt._130-2015_srl_noleggio_pdf_.exe fattura Tiscali numero 026778844.pdf.exe fattura-100543246-sistem-genereted-verified.exe ft._118_-_2015_srl_noleggio__docx_.doc.exe ihre_rechnung_vom_24062015_als_pdf_.exe img_005_apr2015.jpeg.exe info_bank_pdf_xglapuk.exe large_2_03_06_2015jpgjpeg.exe
Dropped files
Seemingly random, regexp: KB[0-9]{8}\.exe
KB07341263.exe (896dec6dd2e1190aa69e3f19bd7c00c9) KB21743115.exe (f7c776865c6e202a19a590e063303016) KB21746240.exe (1c04d9fac2fdc1017b8443de81dabc3c) KB33798926.exe (2d11c7b7d7b418a45a30cf4ba4e938d8) KB07887278.exe (1df302a42144ad240f7b0ee8b165840f) KB36135815.exe (ebb7e22d4a10cbed0d6f1a5be3163078)
Command and Control servers
hxxp://93.115.38 .134/new/stats.php (Italian campaign) hxxp://5.9.253 .153/new/stats.php (German campaign)