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; in a few days, we will publish a whitepaper (part 2/2) 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:

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:

69690f609140db503463daf6a3699f1bf3e2a5a6049cefe7e6437f762040e548 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.

**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:

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

**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:

6ad78f069c3619d0d18eef8281219679f538cfe0c1b6d40b244beb359762cf96 49c5c798689d4a54e5b7099b647b0596fb96b996a437bb8241b5dd76e974c24e e88970fa4892150441c1616028982fe63c875f149cd490c3c910a1c091d3ad49 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 mysterysoft.epac.to 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 dekka.biz[.]tm 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 dns memento.info[.]tm 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