Sigma rule: Potential Powershell ReverseShell Connection

Rule

Title

Potential Powershell ReverseShell Connection

Status

stable

Level

high

Author

FPT.EagleEye, wagga, Nasreddine Bencherchali (Nextron Systems)

Date

2021-03-03

Modified

2023-04-05

File

rules/windows/process_creation/proc_creation_win_powershell_reverse_shell_connection.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects usage of the "TcpClient" class. Which can be abused to establish remote connections and reverse-shells. As seen used by the Nishang "Invoke-PowerShellTcpOneLine" reverse shell and other.

Log source

product

windows

category

process_creation

Detection

selection_img:
    - OriginalFileName:
          - 'PowerShell.EXE'
          - 'pwsh.dll'
    - Image|endswith:
          - '\powershell.exe'
          - '\pwsh.exe'
selection_cli:
    CommandLine|contains|all:
        - ' Net.Sockets.TCPClient'
        - '.GetStream('
        - '.Write('
condition: all of selection_*

False positives (as the rule lists them)

• In rare administrative cases, this function might be used to check network connectivity

Tags

• attack.execution
• attack.t1059.001

MITRE ATT&CK ids this rule names

• T1059.001

References

• https://www.volexity.com/blog/2021/03/02/active-exploitation-of-microsoft-exchange-zero-day-vulnerabilities/
• https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/
• https://github.com/samratashok/nishang/blob/414ee1104526d7057f9adaeee196d91ae447283e/Shells/Invoke-PowerShellTcpOneLine.ps1

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_powershell_reverse_shell_connection.yml