New Variants of Agent.BTZ/ComRAT Found: The Threat That Hit The Pentagon In 2008 Still Evolving; Part 1/2

Written by Omri Ben Bassat

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    Agent.BTZ–also known as ComRAT–is one of the world’s oldest known state-sponsored threats, mainly known for the 2008 Pentagon breach. Technically speaking, Agent.BTZ is a sophisticated user-mode RAT developed and operated by the Turla group in conjunction with Snake/Uroburos rootkit. In the past few months, we conducted research on Agent.BTZ’s code-base and how it evolved using Intezer Code Intelligence™ technology. Based on our research conclusions, we were able to hunt about a dozen new samples and more than seventy previously unknown live IP & DNS addresses indicating the ongoing abuse of satellite internet providers operating in both Africa & the Middle East.

    This is a short memo regarding our findings from the past few months; get more details in Part 2 of this blog, a whitepaper we wrote on Agent.BTZ/ComRAT describing in more details how we found these new variants using our technology, along with a thorough analysis of the new samples.

    Dropper: Although the code itself was written from scratch and has nothing to do with WinRAR, the adversary tried to mimic WinRAR’s SFX installer. Resource data was duplicated, including icons and layouts used by the original installer, as you can see in the following screenshot:Intezer Code Intelligence technology

    Once executed, the dropper installs activeds.dll – a proxy dll which is loaded directly to explorer.exe once the machine reboots. The purpose of this proxy dll is to load the malware’s main payload –
    stdole2.tlb. The dropper then also deletes any previous installation of Agent.BTZ if it exists. This is done using a hard-coded file path:

    • “C:\Documents and Settings\<USER>\Application Data\\Microsoft\\Windows\\Themes\\termsvr32.dll”
    • “C:\Documents and Settings\<USER>\Application Data\\Microsoft\\Windows\\Themes\\pcasrc.tlb”

    **Note: These file names were first used by Agent.BTZ in late 2014, as you can see in this automatic Dr.WEB report

    Once finished, the dropper renames and self delete using the following command line:

    • “C:\WINDOWS\system32\rundll32.exe C:\DOCUME~1\<USER>~1\APPLIC~1\MICROS~1\Windows\stdole2.tlb,UnInstall C:\~$.tmp”

    Samples found:

    1. 69690f609140db503463daf6a3699f1bf3e2a5a6049cefe7e6437f762040e548
    2. 6798b3278ae926b0145ee342ee9840d0b2e6ba11ff995c2bc84d3c6eb3e55ff4

    stdole2.tlb: As previously mentioned, this file is the main component installed by the fake-sfx dropper and loaded by activeds.dll. We extracted the configuration from each sample in order to obtain the c2 address and inner version (“PVer”), which is built into every Agent.BTZ sample. In the past, Agent.BTZ’s developers have used an incremental value to indicate the inner build version, the last known value is 3.26 as published by G-Data in late 2014, It seems that the developers have reacted to G-Data’s publication and have stopped using an incremental value. New variants are now using a different numbering system of 0.8/9.<RANDOM_VALUE>, making it more difficult for researchers to track the exact version of the samples.

    Intezer Code Intelligence technology

    **example configuration extracted from one of the samples – PVer 0.9.1528434231.

    Even without the PVer numbering, we were able to determine using our technology that these samples are from a newer version, which is based on the latest known versions of Agent.BTZ – 3.25 / 3.26. These are the two top files you can see in the following screenshot:

    1. 4e553bce90f0b39cd71ba633da5990259e185979c2859ec2e04dd8efcdafe356(VirusTotal)
    2. 3a6c1aa367476ea1a6809814cf534e094035f88ac5fb759398b783f3929a0db2(VirusTotal)

    Both of these files were uploaded almost three years ago to VT(!)

    Intezer Code Intelligence technology

    **A screenshot from the Intezer Analyze™ product displaying a list of files in our database that share pieces of code with one of the new samples.  These pieces of code are specific to the Turla malware family, and were not seen in any other malicious or legitimate software.

    Samples found:

    1. 6ad78f069c3619d0d18eef8281219679f538cfe0c1b6d40b244beb359762cf96
    2. 49c5c798689d4a54e5b7099b647b0596fb96b996a437bb8241b5dd76e974c24e
    3. e88970fa4892150441c1616028982fe63c875f149cd490c3c910a1c091d3ad49
    4. 89db8a69ff030600f26d5c875785d20f15d45331d007733be9a2422261d16cea

    Indicators of Compromise:

    type indicator notes
    sha256 69690f609140db503463daf6a3699f1bf3e2a5a6049cefe7e6437f762040e548 dropper
    sha256 6798b3278ae926b0145ee342ee9840d0b2e6ba11ff995c2bc84d3c6eb3e55ff4 dropper
    sha256 73db4295c5b29958c5d93c20be9482c1efffc89fc4e5c8ba59ac9425a4657a88 activeds.dll
    sha256 50067ebcc2d2069b3613a20b81f9d61f2cd5be9c85533c4ea34edbefaeb8a15f activeds.dll
    sha256 380b0353ba8cd33da8c5e5b95e3e032e83193019e73c71875b58ec1ed389bdac activeds.dll
    sha256 9c163c3f2bd5c5181147c6f4cf2571160197de98f496d16b38c7dc46b5dc1426 activeds.dll
    sha256 628d316a983383ed716e3f827720915683a8876b54677878a7d2db376d117a24 activeds.dll
    sha256 f27e9bba6a2635731845b4334b807c0e4f57d3b790cecdc77d8fef50629f51a2 activeds.dll
    sha256 a093fa22d7bc4ee99049a29b66a13d4bf4d1899ed4c7a8423fbb8c54f4230f3c activeds.dll
    sha256 6ad78f069c3619d0d18eef8281219679f538cfe0c1b6d40b244beb359762cf96 stdole2.tlb
    sha256 49c5c798689d4a54e5b7099b647b0596fb96b996a437bb8241b5dd76e974c24e stdole2.tlb
    sha256 e88970fa4892150441c1616028982fe63c875f149cd490c3c910a1c091d3ad49 stdole2.tlb
    sha256 89db8a69ff030600f26d5c875785d20f15d45331d007733be9a2422261d16cea stdole2.tlb
    ip 81.199.34[.]150
    dns elephant.zzux[.]com
    dns angrybear.ignorelist[.]com
    dns bigalert.mefound[.]com
    dns bughouse.yourtrap[.]com
    dns getfreetools.strangled[.]net
    dns news100top.diskstation[.]org
    dns pro100sport.mein-vigor[.]de
    dns redneck.yourtrap[.]com
    dns savage.2waky[.]com
    dns tehnologtrade.4irc[.]com
    ip 81.199.160[.]11
    dns forums.chatnook[.]com
    dns goodengine.darktech[.]org
    dns locker.strangled[.]net
    dns simple-house.zzux[.]com
    dns specialcar.mooo[.]com
    dns sunseed.strangled[.]net
    dns whitelibrary.4irc[.]com
    dns bloodpearl.strangled[.]net
    dns getlucky.ignorelist[.]com
    dns proriot.zzux[.]com
    dns fourapi.mooo[.]com
    dns nopasaran.strangled[.]net
    ip 78.138.25[.]29
    dns showme.twilightparadox[.]com
    dns mouses.strangled[.]net
    ip 82.146.175[.]69
    dns mouses.strangled[.]net
    ip 178.219.68[.]242
    dns ftp.fueldust.compress[.]to
    dns ftp.linear.wikaba[.]com
    dns ftp.mysterysoft.epac[.]to
    dns ftp.scroller.longmusic[.]com
    dns ftp.spartano.mefound[.]com
    dns fueldust.compress[.]to
    dns linear.wikaba[.]com
    dns safety.deaftone[.]com
    dns salary.flnet[.]org
    dns scroller.longmusic[.]com
    dns spartano.mefound[.]com
    ip 88.83.25[.]122
    dns robot.wikaba[.]com
    ip 41.223.91[.]217
    dns smileman.compress[.]to
    dns decent.ignorelist[.]com
    dns disol.strangled[.]net
    dns eraser.2waky[.]com
    dns filelord.epac[.]to
    dns justsoft.epac[.]to
    dns smuggler.zzux[.]com
    dns sport-journal.twilightparadox[.]com
    dns sportinfo.yourtrap[.]com
    dns stager.ignorelist[.]com
    dns tankos.wikaba[.]com
    dns grandfathers.mooo[.]com
    dns homeric.mooo[.]com
    dns jamming.mooo[.]com
    dns pneumo.mooo[.]com
    dns razory.mooo[.]com
    dns anger.scieron[.]com
    dns gantama.mefound[.]com
    dns letgetbad.epac[.]to
    dns rowstate.epac[.]to
    ip 196.43.240[.]177
    dns bughouse.yourtrap[.]com
    dns news100top.diskstation[.]org
    ip 169.255.102[.]240
    dns harm17.zzux[.]com
    dns mountain8.wikaba[.]com
    sha256 0e0045d2c4bfff4345d460957a543e2e7f1638de745644f6bf58555c1d287286 other
    sha256 bdcc7e900f10986cdb6dc7762de35b4f07f2ee153a341bef843b866e999d73a3 other
    sha256 fac13f08afe2745fc441ada37120cebce0e0aa16d03a03e9cda3ec9384dd40f2 backdoor
    sha256 bae62f7f96c4cc300ec685f42eb451388cf50a13aa624b3f2a019d071fddaeb1 other

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    Omri Ben Bassat

    Ex-officer in the IDF CERT. Malware analyst and a reverse engineer with vast experience in dealing with nation-state sponsored cyber attacks. Omri is the creator of Master of Puppets (MoP)—an open-source framework for reverse engineers who wish to create and operate trackers for new malware found in the wild—which was presented during the Black Hat USA 2019 Arsenal.

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