Sigma detection rules, expert-reviewed

Suspicious Hidden PowerShell Downloading Payload via ClickFix (via process_creation)

This rule detects PowerShell launched with a hidden window that immediately downloads and executes remote content. The ClearFake ClickFix lure tricks users into pasting a mixed-case PowerShell command that runs with a suppressed window to fetch its next stage. A hidden PowerShell window combined with download and execution cmdlets is characteristic of ClickFix social engineering.

Suspicious Double Extension docx Executable Execution (via process_creation)

This rule detects execution of a binary whose filename carries a double extension combining a document extension and padded spaces before .exe, the lure delivery technique used by Kimsuky against Japanese organizations. The masqueraded filename is designed to trick users into launching an executable they believe is a Word document.

Malicious DLL Side-Loading of vcomp100 via converter.exe

This rule detects the ImageMagick converter.exe loading vcomp100.dll from outside the Windows system directories. The IDAT loader chain delivering Vidar and ACR stealers abused this signed binary to side-load a malicious vcomp100.dll and execute stager code under a trusted process.

In-Memory Remcos RAT Keylog Store Created Under ProgramData rema (via file_event)

This rule detects creation of the logs.dat file inside the ProgramData rema directory, the local store used by this Remcos RAT variant to buffer keystroke and clipboard capture before exfiltration. Adversaries leverage this staging file to accumulate stolen input on disk, making detection of the fixed path a useful indicator of active collection.

DLL Side-Loading of NvSmartMax via NvSmart Host Process

This rule detects the nvSmartEx.exe host loading NvSmartMax.dll from outside the legitimate NVIDIA program directory, the DLL side-loading pair used by DeadRinger actors to run implant code. A trusted NVIDIA binary loading its companion DLL from an unexpected path indicates search-order hijacking.

Malicious Microsoft Defender Default Action Changed to Allow Any Threat - Command (via process_creation)

This rule detects change Defender default action to allow any threats.

Malicious DNS Hosts File Accessed via Network Share (via security)

This rule detects attempt read the Hosts file content via network share.

Malicious Akira Ransomware Execution via Encryption Command-Line Parameters

This rule detects process execution using the distinctive encryption command-line parameters of the Akira ransomware encryptor, matching intrusions where a renamed akira.exe is run against mounted network shares. The switches control encryption scope and percentage across targeted paths and shares. Detecting these parameters catches the encryptor even when the binary is renamed to evade name-based controls.

Malicious Windows Defender Disabling via DC.exe Defender Control by Elpaco Ransomware

This rule detects execution of the Defender Control utility (DC.exe) with a disable switch to turn off Windows Defender. This behavior is used by the Elpaco ransomware, a Mimic variant, to blind endpoint protection before encryption. Disabling defenses removes the primary barrier to file encryption and lateral movement, making early detection critical.

Suspicious Firewall Configuration Enumerated - PowerShell (via powershell)

This rule detects extract current Windows firewall configuration to prepare an attack.

Suspicious Mock Trusted Directory with Trailing Space (via process_creation)

This rule detects the DBatLoader UAC bypass technique that creates a mock system directory whose name carries a trailing space before the System32 segment to satisfy trusted-directory checks. Any process image path containing Windows followed by a space and then a backslash indicates this masquerade. Legitimate Windows binaries never execute from such a path.

Suspicious Hidden PowerShell Encoded IEX Execution

This rule detects PowerShell launched with stealth flags together with in-memory execution of Base64 content, matching the spyware loader from the Pakistan-targeted fake dating app campaign. The combination of hidden window, bypassed policy and IEX-decoded payload indicates fileless execution of downloaded malware.

Malicious DeadLock Ransomware Encrypted File Extension Creation (via file_event)

This rule detects creation of files carrying the .dlock extension appended by the DeadLock ransomware encryptor as reported by Group-IB. Adversaries rename encrypted files with this extension during impact, so these writes indicate active DeadLock encryption on the host.

Suspicious SSH Reverse Tunnel via Renamed plink Utility on Triofox Host

This rule detects renamed plink or putty binaries sihosts.exe and silcon.exe establishing a reverse SSH tunnel with the -R flag as observed after Triofox exploitation. Attackers proxy RDP over an outbound tunnel to a non standard port to maintain covert remote access.

Suspicious Astaroth Spambot Browser Profile Staging Directory (via file_event)

This rule detects creation of the browser profile staging directory used by the Astaroth spambot component. Astaroth copies the victim browser profile into a ChromeAuto directory under the public temp folder to drive an automated headless browser session. This directory pattern is a high-fidelity host indicator.