Malware analysis 06-08-19.md

Malware analysis on Gamaredon APT campaign (06-08-19)

Table of Contents

• Malware analysis
  • Initial vector
  • VBS and Powershell script
  • Final PE
  • Cyber kill chain
• Cyber Threat Intel
• IOC
• References MITRE ATT&CK Matrix
• Links
  • Original Tweet
  • Link Anyrun
  • Ref previous analysis

Malware-analysis

Initial vector

The SFX archive executes for get system informations and the architecture in using the function GetNativeSystemInfo and Getsysteminfo who are using for know the good parameters for the SFX installer.

Once this done, this show a fake window of Word in using riche020.dll method. Define the language of thread in Russian.The execution of the code is do in another thread who run the malicious parts in the background.

We can observe a trace of a capacity to extract a lnk file which are used in a similar sample.

This drops the cmd file and PE file as txt file in the temp folder with a random name.

Finally, this execute by call shell and runas the cmd file.

VBS and Powershell script

Its create the vbs and ps1 file by redirection of the console output. By the DOS commands, this create a schedule task as persistence, modify the proxy settings, execute the files, launch the fake document and delete all the files as anti-forensic method.

The vbs file check the version of Word and disable some security features.

The powershell script collect the system informations and edit the proxy seetings and the url send to the C2 with the GUID of the computer.

We can see on the obfuscated strings, that some patterns have been generated and randomized by a DOS obfuscate tool.

Like observed with muddywater group, this repeats until the group edit a URL with the next payload if the target is interesting.

Final PE

We can see that the file have the capacity to parse a FTP share and perform the current action (upload/download)

We can observe too that the payload can receive a proxy configuration and parse it too.

A progress bar can be observe wh o indicate that the PE can show the status of the operations

This PE file uses the OpenSSL, SMTP, FTP and various algorithms libraries in C, this a compiled version of Wget.

We can parse and see all the algoritms available for Wget

This check the connectivity to internet by requesting the DNS of Google and use the shellscript.exe for try to download by the edited URL. This version of Wget is used on many campaigns of this group since 2017.

Cyber kill chain

The process graph resume the cyber kill chain used by the attacker.

Cyber Threat Intel

The C2 is host by a provider in Russia.This seems be a sample of the campaign of Gamaredon group in June 2018 by the very similar TTPs.

References MITRE ATT&CK Matrix

List of all the references with MITRE ATT&CK Matrix

Enterprise tactics	Technics used	Ref URL
Execution	T1059 - Starts CMD.EXE for commands execution T1106 - Execution through API T1053 - Scheduled Task T1064 - Scripting	https://attack.mitre.org/techniques/T1059 https://attack.mitre.org/techniques/T1106 https://attack.mitre.org/techniques/T1053 https://attack.mitre.org/techniques/T1064
Persistence	T1053 - Scheduled Task	https://attack.mitre.org/techniques/T1053
Privilege Escalation	T1053 - Scheduled Task	https://attack.mitre.org/techniques/T1053
Defense Evasion	T1112 - Modify Registry T1064 - Scripting	https://attack.mitre.org/techniques/T1112 https://attack.mitre.org/techniques/T1064
Discovery	T1012 - Query Registry	https://attack.mitre.org/techniques/T1012

Indicators Of Compromise (IOC)

List of all the Indicators Of Compromise (IOC)

Indicator	Description
02013f0c6767eb7f0538510ba6ede0103e797fa7b9bc2733d00e3710702fdf1c.scr	02013f0c6767eb7f0538510ba6ede0103e797fa7b9bc2733d00e3710702fdf1c
FDGSKGN.vbs	630c0c86faf828bc4645526ca58b855d1a2db57cca0e406c1d5b7e2de88a1322
PowerShellCertificates_C4BA3647.ps1	8f33ce796ee08525d32f5794ebd355914140e43e4b63e09b384dabda93a8b22c
9856.txt	a48ad33695a44de887bba8f2f3174fd8fb01a46a19e3ec9078b0118647ccf599
176.57.215.22	IP C2
http[:]//shell-create.ddns.net/	URL request
shell-create.ddns.net	Domain C2

This can be exported as JSON format Export in JSON

Links

• Original tweet: https://twitter.com/Timele9527/status/1157458188792262656
• Anyrun Link: 02013f0c6767eb7f0538510ba6ede0103e797fa7b9bc2733d00e3710702fdf1c.scr
• Ref previous analysis : gamaredon eastern europe attacks