[New Rules] Several GitHub Related Rules

[Aegrah]

Summary

Adds several new detection rules leveraging the GitHub Audit API, based on a report by trigger.dev, where a post-compromise analysis was conducted. These rules were created to cover the different IoCs identified in this report.

GitHub Secret Scanning Disabled

Detects when GitHub Secret Scanning is disabled for a repository. Adversaries may disable secret scanning to evade detection of hardcoded secrets, such as API keys or credentials, that could be used for further compromise or data exfiltration.

GitHub Exfiltration via High Number of Repository Clones by User

Detects a high number of repository cloning actions by a single user within a short time frame. Adversaries may clone multiple repositories to exfiltrate sensitive data.

High Number of Closed Pull Requests by User

Detects a high number of closed pull requests by a single user within a short time frame. Adversaries may close multiple pull requests to disrupt development workflows or hide malicious changes.

Several Failed Protected Branch Force Pushes by User

Detects a high number of failed force push attempts to protected branches by a single user within a short time frame. Adversaries may attempt multiple force pushes to overwrite commit history on protected branches, potentially leading to data loss or disruption of development workflows.

High Number of Protected Branch Force Pushes by User

Detects a high number of force push actions to protected branches by a single user within a short time frame. Adversaries may perform force pushes to overwrite commit history on protected branches, potentially leading to data loss or disruption of development workflows.

New GitHub Personal Access Token (PAT) Added

Detects when a new GitHub Personal Access Token (PAT) is created. Adversaries may create new PATs to maintain persistent access to a compromised account or to escalate privileges within an organization.

Github Activity on a Private Repository from an Unusual IP

Detects when there is activity on a private GitHub repository from an unusual IP address. Adversaries may access private repositories from unfamiliar IPs to exfiltrate sensitive code or data, potentially indicating a compromise or unauthorized access.

GitHub Private Repository Turned Public

Detects when a private GitHub repository is changed to public visibility. Adversaries may change repository visibility to public in order to exfiltrate sensitive code or data, potentially indicating a compromise or unauthorized access.

[github-actions]

Rule: New - Guidelines

These guidelines serve as a reminder set of considerations when proposing a new rule.

Documentation and Context

• Detailed description of the rule.
• List any new fields required in ECS/data sources.
• Link related issues or PRs.
• Include references.

Rule Metadata Checks

• creation_date matches the date of creation PR initially merged.
• min_stack_version should support the widest stack versions.
• name and description should be descriptive and not include typos.
• query should be inclusive, not overly exclusive, considering performance for diverse environments. Non ecs fields should be added to non-ecs-schema.json if not available in an integration.
• min_stack_comments and min_stack_version should be included if the rule is only compatible starting from a specific stack version.
• index pattern should be neither too specific nor too vague, ensuring it accurately matches the relevant data stream (e.g., use logs-endpoint.process-* for process data).
• integration should align with the index. If the integration is newly introduced, ensure the manifest, schemas, and new_rule.yaml template are updated.
• setup should include the necessary steps to configure the integration.
• note should include any additional information (e.g. Triage and analysis investigation guides, timeline templates).
• tags should be relevant to the threat and align/added to the EXPECTED_RULE_TAGS in the definitions.py file.
• threat, techniques, and subtechniques should map to ATT&CK always if possible.

New BBR Rules

• building_block_type should be included if the rule is a building block and the rule should be located in the rules_building_block folder.
• bypass_bbr_timing should be included if adding custom lookback timing to the rule.

Testing and Validation

• Provide evidence of testing and detecting the expected threat.
• Check for existence of coverage to prevent duplication.