agenttesla | 3845a8f1b22212dbb08c6a9c95c3cc765a2d9676dbe367acf2c24f845b264bf6

General

Target
gunzipped.exe
Size 602KB
Sample201109-b9y332dkcn
SHA256 3845a8f1b22212dbb08c6a9c95c3cc765a2d9676dbe367acf2c24f845b264bf6
MD5 8ee650d9c83e5e105e523e1431cd6d58
SHA1 96c13097506af7965036de864bf0ff48a842af5f
SHA512 b071921b412e8a6dd1e3f2676cb836b7eb013d5c24a1d4976150b365f531a7c27480f196d6e9d4ee9086bdd7d66c39817c7ce5ce6b11fa6fe22eb6fa58292c4a
MD5 SHA1 SHA512

Score

10^/10

agenttesla evasion keylogger rezer0 spyware stealer trojan

Malware Config

Extracted

Credentials

Protocol
smtp
Host
smtp.yandex.com
Port
587
Username
[email protected]
Password
gatefee22

Extracted

Family

agenttesla

Credentials

Protocol
smtp
Host
smtp.yandex.com
Port
587
Username
[email protected]
Password
gatefee22

Signatures

AgentTesla
Agent Tesla is a remote access tool (RAT) written in visual basic.
keylogger trojan stealer spyware agenttesla

AgentTesla Payload 2 IoCs

resource	yara_rule
behavioral2/memory/4448-15-0x0000000000400000-0x0000000000450000-memory.dmp	family_agenttesla
behavioral2/memory/4448-16-0x000000000044A07E-mapping.dmp	family_agenttesla

Looks for VirtualBox Guest Additions in registry 2 TTPs
evasion

Query Registry
T1012

Virtualization/Sandbox Evasion
T1497

rezer0 1 IoCs

Detects ReZer0, a packer with multiple versions used in various campaigns.

rezer0

resource	yara_rule
behavioral2/memory/4760-11-0x00000000073E0000-0x0000000007430000-memory.dmp	rezer0

Looks for VMWare Tools registry key 2 TTPs
evasion

Query Registry
T1012

Virtualization/Sandbox Evasion
T1497

Checks BIOS information in registry 2 TTPs 2 IoCs

BIOS information is often read in order to detect sandboxing environments.

Query Registry

T1012

System Information Discovery

T1082

description	ioc	Process
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\SystemBiosVersion	gunzipped.exe
Key value queried	\REGISTRY\MACHINE\HARDWARE\DESCRIPTION\System\VideoBiosVersion	gunzipped.exe

Reads data files stored by FTP clients 2 TTPs
Tries to access configuration files associated with programs like FileZilla.
spyware

Data from Local System
T1005

Credentials in Files
T1081
Reads user/profile data of local email clients 2 TTPs
Email clients store some user data on disk where infostealers will often target it.
spyware

Data from Local System
T1005

Credentials in Files
T1081
Reads user/profile data of web browsers 2 TTPs
Infostealers often target stored browser data, which can include saved credentials etc.
spyware

Data from Local System
T1005

Credentials in Files
T1081

Maps connected drives based on registry 3 TTPs 2 IoCs

Disk information is often read in order to detect sandboxing environments.

Query Registry

T1012

Peripheral Device Discovery

T1120

System Information Discovery

T1082

description	ioc	Process
Key opened	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Services\Disk\Enum	gunzipped.exe
Key value queried	\REGISTRY\MACHINE\SYSTEM\ControlSet001\Services\Disk\Enum\0	gunzipped.exe

Suspicious use of SetThreadContext 1 IoCs

description	pid	Process	procid_target
PID 4760 set thread context of 4448	4760	gunzipped.exe	79

Enumerates physical storage devices 1 TTPs
Attempts to interact with connected storage/optical drive(s). Likely ransomware behaviour.

System Information Discovery
T1082

Creates scheduled task(s) 1 TTPs 1 IoCs

Schtasks is often used by malware for persistence or to perform post-infection execution.

persistence

Scheduled Task

T1053

pid	Process
3436	schtasks.exe

Suspicious behavior: EnumeratesProcesses 5 IoCs

pid	Process
4760	gunzipped.exe
4760	gunzipped.exe
4760	gunzipped.exe
4448	gunzipped.exe
4448	gunzipped.exe

Suspicious use of AdjustPrivilegeToken 2 IoCs

description	pid	Process
Token: SeDebugPrivilege	4760	gunzipped.exe
Token: SeDebugPrivilege	4448	gunzipped.exe

Suspicious use of SetWindowsHookEx 1 IoCs

pid	Process
4448	gunzipped.exe

Suspicious use of WriteProcessMemory 11 IoCs

description	pid	Process	procid_target
PID 4760 wrote to memory of 3436	4760	gunzipped.exe	77
PID 4760 wrote to memory of 3436	4760	gunzipped.exe	77
PID 4760 wrote to memory of 3436	4760	gunzipped.exe	77
PID 4760 wrote to memory of 4448	4760	gunzipped.exe	79
PID 4760 wrote to memory of 4448	4760	gunzipped.exe	79
PID 4760 wrote to memory of 4448	4760	gunzipped.exe	79
PID 4760 wrote to memory of 4448	4760	gunzipped.exe	79
PID 4760 wrote to memory of 4448	4760	gunzipped.exe	79
PID 4760 wrote to memory of 4448	4760	gunzipped.exe	79
PID 4760 wrote to memory of 4448	4760	gunzipped.exe	79
PID 4760 wrote to memory of 4448	4760	gunzipped.exe	79

C:\Users\Admin\AppData\Local\Temp\gunzipped.exe
"C:\Users\Admin\AppData\Local\Temp\gunzipped.exe"
1⤵
- Checks BIOS information in registry
- Maps connected drives based on registry
- Suspicious use of SetThreadContext
- Suspicious behavior: EnumeratesProcesses
- Suspicious use of AdjustPrivilegeToken
- Suspicious use of WriteProcessMemory
PID:4760
- C:\Windows\SysWOW64\schtasks.exe
  "C:\Windows\System32\schtasks.exe" /Create /TN "Updates\LntpkSoqbdIB" /XML "C:\Users\Admin\AppData\Local\Temp\tmp3ACC.tmp"
  2⤵
  - Creates scheduled task(s)
  PID:3436
- C:\Users\Admin\AppData\Local\Temp\gunzipped.exe
  "{path}"
  2⤵
  - Suspicious behavior: EnumeratesProcesses
  - Suspicious use of AdjustPrivilegeToken
  - Suspicious use of SetWindowsHookEx
  PID:4448