Researchers Discover New variants of APT34 Malware

Written by Jay Novak and Matthew Pennington

Table 1. Relationship between original binary and three discovered variants.

Table 1. Relationship between original binary and three discovered variants. (Use the scrollbar to view the content on the far right.)

As you can see from Table 1 above, these files exhibit many similar characteristics and behaviors.  Most of the differences appear to be cosmetic and do not affect the underlying functionality. Our analysts took a closer look at the C2 domain poison-frog[.]club, which is used in 3 of the 4 files, and found that it overlaps with the findings of the FireEye report. The domain resolved to 82.102.14.219 from at least August 2017 until December 2017. Additional domains that resolved to that IP during that time frame are dns-update[.]club, hpserver[.]online, and anyportals[.]com which were all mentioned in the FireEye report. The other C2 domain used, proxycheker[.]pro, resolved to 94.23.172.164 and 185.15.247.147, with 185.15.247.147 also hosting dns-update[.]club during that time frame. This new-found evidence, in combination with similar versions of POWRUNER and BONDUPDATER, the existence of the same debug strings in the code of each variant, and the overlapping infrastructure indicate that these three new binaries are also associated with APT34 operations.

The DGA domain generation algorithm used in one version of the BONDUPDATER backdoor is broken down into two parts: send and receive.  If data is being sent, then the following format is used:

DGA domain generation algorithm - Send
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  1. This is created from combining a unique ID (generated from the MAC address or encoded version of whoami) along with two other parameters which are inserted at two different random offsets in the unique ID
  2. Random characters generated from: -join ((48 .. 57)+(65 .. 70) | Get-Random  -Count (%{ Get-Random -InputObject (1 .. 7) }) | %{ [char]$_ })
  3. Hardcoded "A" 
  4. Two random offset values referenced in #1.
  5. Hardcoded "7"
  6. Data Chunk being sent
  7. Encoded Filename being sent
  8. Hardcoded domain ".poison-frog[.]club"

If data is being received, then the following format is used:

DGA domain generation algorithm - Receive
  1. This is created from combining a unique ID (generated from the MAC address or encoded version of whoami) along with two other parameters which are inserted at two different random offsets in the unique ID
  2. Random characters generated from: -join ((48 .. 57)+(65 .. 70) | Get-Random  -Count (%{ Get-Random -InputObject (1 .. 7) }) | %{ [char]$_ })
  3. Hardcoded "A" 
  4. Two random offset values referenced in #1.
  5. Hardcoded "7" 
  6. Hardcoded domain ".poison-frog[.]club"

The Domain Generating Algorithm (DGA) generation process is different than what was previously mentioned in the FireEye report.  However, it would still be detected using Dark Labs' custom DGA detection mechanism.

In early January 2018, ClearSky Cyber Security tweeted about two new malware samples attributed to Oilrig/APT34.  These samples were being deployed via a malicious .chm (Compiled HTML Help File) file.  ClearSky provides a link to a Google document they use for "Raw Threat Intelligence" which contained additional IOCs associated with this campaign. Two hashes provided in that document are for versions of POWRUNER (MD5: BED81E58EF8FF0B073E371D433A08855) and BONDUPDATER (MD5: 63D6B1933F7330358A8FBFAF77532133). These two backdoors contain a reference to another C2 domain, www.window5[.]win. Using the custom tool developed in Dark Labs, we were able to pivot from these samples and discover an additional sample each of POWRUNER and BONDUPDATER.

These two new samples exhibit similar behavior to the samples mentioned in the FireEye report.  However, there are a few slight differences - namely the use of a new C2 domain and URI, www.window5[.]win/update.aspx.  At writing time of this post, that domain resolves to 185.181.8.246.  Current research indicates that IP does not host any other domains publicly available.  Additionally, the %PUBLIC%\Java location (e.g. C:\Users\Public\Java) is used for a staging directory in this version of POWRUNER.

Source

Hash Value

C2 Domain

Details

FireEye Report

C9F16F0BE8C77F0170B9B6CE876ED7FB

proxychecker[.]pro

  • Contains both POWRUNER and BONDUPDATER
  • Communicates with C2 via proxychecker[.]pro/update_wapp.aspx
  • POWRUNER appears to not have the ability to save files

ATH Tool

87FB0C1E0DE46177390DE3EE18608B21

poison-frog[.]club

  • Contains both POWRUNER and BONDUPDATER
  • Communicates with C2 via poison-frog[.]club/update_wapp.aspx
  • POWRUNER appears to not have the ability to save files

ATH Tool

A602A7B6DEADC3DFB6473A94D7EDC9E4

poison-frog[.]club

  • Contains both POWRUNER and BONDUPDATER
  • Communicates with C2 via poison-frog[.]club/update_wapp.aspx
  • POWRUNER appears to not have the ability to save files

RetroHunt

4EA656D10BEAC05D69252D270592

poison-frog[.]club

  • Contains only POWRUNER
  • Communicates with C2 via poison-frog[.]club/update_wapp.aspx
  • POWRUNER appears to not have the ability to save files
  • POWRUNER contains more Base64 obfuscation effort than other versions

000C20009204A601

7D

A

56

7

6556666775466767667566765657661c79e4f73cd932f3f64ca161c45041

336662009e6a

.poison-frog.club

1

2

3

4

5

6

7

8

0800C0092904A601

02

A

51

7

.poison-frog.club

1

2

3

4

5

6

Source

Hash Value

C2 Domain

Details

ClearSky Cyber Security

BED81E58EF8FF0B073E371D433A08855

window5[.]win

  • POWRUNER
  • Communicates with C2 via www.window5[.]win/update.aspx

ClearSky Cyber Security

63D6B1933F7330358A8FBFAF77532133

window5[.]win

  • BOUNDATER
  • Communicates via DGA based DNS to wondow5[.]win

ATH Tool

CBE2F69D9EF39093D8645D3C93FD7F21

window5[.]win

  • POWRUNER
  • Communicates with C2 via www.window5[.]win/update.aspx

ATH Tool

277FF86501B98A4FF8C945AC4D4A7C53

window5[.]win

  • BONDUPDATER
  • Communicates via DGA based DNS to window5[.]win

Table 2. Relationship between original two samples and two discovered variants. (Use the scrollbar to view the content on the far right.)

 

IOC - Network

Domain/IP Address

Description

proxycheker[.]pro

C2

poison-frog[.]club

C2

window5[.]win

C2

82.102.14.219

Has resolved poison-frog[.]club, dns-update[.]club, hpserver[.]online & anyportals[.]com

94.23.172.164

Has resolved proxycheker[.]pro

185.15.247.147

Has resolved proxycheker[.]pro & dns-update[.]club

185.181.8.246

Has resolved window5[.]win

IOC - Endpoint

Filename

Description

MD5 Hash

dupdatechecker.exe

Dropper of POWRUNER and BONDUPDATER

C9F16F0BE8C77F0170B9B6CE876ED7FB

exeruner_new.exe

Dropper of POWRUNER and BONDUPDATER

87FB0C1E0DE46177390DE3EE18608B21

exeruner.exe

Dropper of POWRUNER and BONDUPDATER

A602A7B6DEADC3DFB6473A94D7EDC9E4

exeruner_new.exe

Dropper of POWRUNER

4EA656D10BE1D6EAC05D69252D270592

GoogleUpdateschecker.vbs

Deploys POWRUNER

6F2CA6D892CCA631C191233CB89D9B93

JavaUpdates

Scheduled Task to run VBS script

0681F2459EDF28DCD99493AE8A6398D5

rUpdateChecker.ps1

Sets up scheduled task to deploy POWRUNER

EE93A172937D37D3152D694331E59A21

GoogleUpdateTasks.vbs

Deploys POWRUNER and BONDUPDATER

F0B278427C8841C5D1A79ED2631B1522

JavaUpdatesTasksHosts

Scheduled Task to run VBS script

52973212E6373585F55B4DD207D890FF

rUpdateChecker.ps1

Sets up scheduled task to deploy POWRUNER and BONDUPDATER

06D537AF8C43F65FC467781B01047E5C

GoogleUpdateschecker.vbs

Deploys POWRUNER and BONDUPDATER

33E86AB6621F3DB7CD7E37CAF42C95E5

JavaUpdates

Scheduled Task to run VBS script

517D1D51414019272849E7C67E622597

rUpdateChecker.ps1

Sets up scheduled task to deploy POWRUNER and BONDUPDATER

614DDCCDCAF73172C1216D812595394C

UpdateCheckers.ps1

BONDUPDATER

1DE8F76404EB799C780DA5830915A17E

dUpdateCheckers.ps1

BONDUPDATER

27ACDFAB0A264B4EBD4DD16DAE6C4E0E

GoogleUpdates.vbs

Deploys POWRUNER and BONDUPDATER

D9BBB27B0C5249D681179D234BFF60DE

JavaUpdatesTask

Scheduled Task to run VBS script

347929555E8D7174D82356F47A054106

rUpdateChecker.ps1

Sets up scheduled task to deploy POWRUNER and BONDUPDATER

C3572009CA311F44A99C4FAB3F3DFF92

hxyz.ps1

POWRUNER

BED81E58EF8FF0B073E371D433A08855

dxyz.ps1

BONDUPDATER

63D6B1933F7330358A8FBFAF77532133

unknown

POWRUNER

CBE2F69D9EF39093D8645D3C93FD7F21

unknown

BONDUPDATER

277FF86501B98A4FF8C945AC4D4A7C53

Yara Signature for the dropper

{
  strings:
  $exeruner_string_1 = "C:\\Users\\aaa\\documents\\visual studio 2015\\Projects\\exeruner\\exeruner\\obj\\Debug\\exeruner.pdb"
  $exeruner_string_2 = "C:\\Users\\aaa\\Desktop\\test\\exeruner\\exeruner\\obj\\Debug\\exeruner_new.pdb"
       
    condition:
        $exeruner_string_1 or $exeruner_string_2
}

 

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By diving deeper and pivoting on known indicators using techniques developed and honed by our experienced analysts, the indicator lifecycle can diversify discovery. In this case, analysts discovered additional unreported, yet campaign associated IOCs that can be used for further detection. Additionally, our analysts also developed YARA signatures for static detection, and TTP based signatures to deploy to EDR tools or for hunting through endpoint telemetry data.  

The Booz Allen Dark Labs Advanced Threat Hunt team recommends deploying detection to endpoints for the hashes listed above and perform a retroactive search for the domains and IPs in SIEM logs. We also recommend the use of telemetry data collected via EDR tools to continuously hunt for this behavior. Monitoring for the behavior or TTP is a critical step because although IOCs can be used for detection and discovery, they can in many cases be changed cheaply and easily. Our Advanced Threat Hunt team always recommends a robust proactive approach to threat hunting with a focus on behavioral detection.

Please contact us if you would like to learn more about Dark Labs Advanced Threat Hunt, or if you are interested in joining our team. 

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