Add KernelCryptoDriverAbuse signature for ransomware detection

[kevross33]

This detects a process that is using the KsecDD to mass encrypt data (likely ransomware encrypting files). It also limits the marked calls to 20.

Lockbit

[gemini-code-assist]

Summary of Changes

Hello @kevross33, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a significant enhancement to ransomware detection capabilities by adding a new signature that specifically targets suspicious interactions with the Windows Kernel Security Device Driver (KsecDD). The new detection logic focuses on identifying processes that perform an unusually high volume of IOCTL calls to KsecDD, which is a strong indicator of hardware-accelerated mass encryption often employed by ransomware or wiper malware. This aims to provide more robust and accurate threat detection.

Highlights

• New Signature Added: A new signature, KernelCryptoDriverAbuse, has been introduced to detect ransomware and wiper activity.
• KsecDD Monitoring: The signature monitors for excessive IOCTL calls to the Kernel Security Device Driver (KsecDD), which is indicative of hardware-accelerated mass encryption.
• False Positive Reduction: Common browser processes (e.g., chrome.exe, firefox.exe) are ignored to reduce potential false positives.
• Call Marking Limit: Relevant API calls are marked up to a limit of 20 per process interacting with KsecDD.
• Alert Threshold: An alert is triggered if a process makes more than 50 IOCTL calls to KsecDD.

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Changelog

• modules/signatures/windows/ransomware_crypto.py
  • Added the KernelCryptoDriverAbuse signature to detect ransomware and wiper activity by monitoring excessive IOCTL calls to the Kernel Security Device Driver (KsecDD).

Activity

• No specific activity has been recorded for this pull request yet.

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[gemini-code-assist]

Code Review

This pull request adds a new signature, KernelCryptoDriverAbuse, to detect potential ransomware activity by monitoring IOCTL calls to KsecDD. The overall logic is sound. I've provided a suggestion to improve robustness by handling missing process information more gracefully. I've also included recommendations to enhance maintainability by replacing magic numbers with named constants.

[gemini-code-assist]

The current implementation does not handle cases where process_id is missing, which could lead to None being used as a dictionary key and incorrectly grouping unrelated events. Additionally, if process_name is an empty string, it is still processed, which can lead to uninformative report messages. It's better to exit early if either pid or pname is missing or invalid.

Suggested change

	pname = process.get("process_name", "").lower()
	if pname in self.ignore_procs:
	return None
	pid = process.get("process_id")
	pid = process.get("process_id")
	if not pid:
	return None
	pname = process.get("process_name", "").lower()
	if not pname or pname in self.ignore_procs:
	return None

[gemini-code-assist]

The magic number 20 is used here as a threshold for marking calls. To improve readability and maintainability, consider defining this as a class-level constant (e.g., MAX_MARKED_CALLS = 20) and referencing it here. This makes the code's intent clearer and simplifies future adjustments.

[gemini-code-assist]

The magic number 50 is used here as a threshold for triggering the signature. To improve readability and maintainability, consider defining this as a class-level constant (e.g., IOCTL_THRESHOLD = 50) and referencing it here. This makes the code's intent clearer and simplifies future adjustments.