Add UAC privilege check signature for process tokens

[kevross33]

Example Conti ransomware

[gemini-code-assist]

Summary of Changes

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This pull request introduces a new Cuckoo Sandbox signature designed to identify malicious behavior related to privilege escalation. Specifically, it targets the detection of processes attempting to determine their User Account Control (UAC) elevation status or verify Administrator group membership, a common tactic used by malware, including ransomware, to assess its privileges.

Highlights

• New Cuckoo Signature for UAC Checks: A new Cuckoo Sandbox signature, 'PrivilegeElevationCheck', has been added to detect attempts by processes to query their UAC elevation status or check for Administrator privileges using Windows API calls like 'NtQueryInformationToken', 'GetTokenInformation', and 'CheckTokenMembership'.

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Changelog

• modules/signatures/windows/bypass_uac_privilegecheck.py
  • Added a new Cuckoo signature 'PrivilegeElevationCheck' to detect UAC and administrator privilege checks.

Activity

• No human activity has been recorded on this pull request yet.

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[gemini-code-assist]

Code Review

This pull request introduces a new signature, PrivilegeElevationCheck, to detect when a process queries for its token information to check for administrator privileges or UAC elevation status. The implementation is clear and correctly identifies the relevant API calls and parameters. I've provided a few suggestions to improve code readability, maintainability, and add a minor performance optimization.

[gemini-code-assist]

For a minor performance improvement, you can add an early exit at the beginning of this method. Once a match is found and self.ret is set to True, there's no need to process subsequent API calls.

        if self.ret:
            return

        api = call["api"]