Skip to content

YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_PS1_Combo_Transfersh_Feb24

Detects suspicious PowerShell command that downloads content from transfer.sh as often found in loaders

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth
Date
2024-02-23
Modified
2024-04-24
Score / Quality
70 / 85

What this rule detects

Detects suspicious PowerShell command that downloads content from transfer.sh as often found in loaders

It defines 4 patterns (4 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

susp-ps1-combo-transfersh-feb24.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_PS1_Combo_Transfersh_Feb24 : SCRIPT
{
	meta:
		description = "Detects suspicious PowerShell command that downloads content from transfer.sh as often found in loaders"
		author = "Florian Roth"
		id = "fd14cca5-9cf8-540b-9d6e-39ca2c267272"
		date = "2024-02-23"
		modified = "2024-04-24"
		reference = "https://www.huntress.com/blog/slashandgrab-screen-connect-post-exploitation-in-the-wild-cve-2024-1709-cve-2024-1708"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_connectwise_screenconnect_vuln_feb24.yar#L120-L135"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "64d4343ecdcbc4a28571557bec2f31c1ff73c2ecf63d0feaa0a71001bb9bf499"
		score = 70
		quality = 85
		tags = "SCRIPT"

	strings:
		$x1 = ".DownloadString('https://transfer.sh"
		$x2 = ".DownloadString(\"https://transfer.sh"
		$x3 = "Invoke-WebRequest -Uri 'https://transfer.sh"
		$x4 = "Invoke-WebRequest -Uri \"https://transfer.sh"

	condition:
		1 of them
}

Strings (4 patterns)

IdentifierTypeValueModifiers
$x1text".DownloadString('https://transfer.sh"
$x2text".DownloadString(\"https://transfer.sh"
$x3text"Invoke-WebRequest -Uri 'https://transfer.sh"
$x4text"Invoke-WebRequest -Uri \"https://transfer.sh"

Condition

1 of them

In plain words (Heuristic)

  • At least 1 patterns in the rule must match.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

Open in editor

References

Licence & attribution

Author: Florian Roth

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: fd14cca5-9cf8-540b-9d6e-39ca2c267272

Tags:SCRIPT