Binary Self Deletion

Quick Explanation

The binary_self_deletion detection recipe identifies instances where a binary file is executed and then promptly unlinked (deleted) from the filesystem. This behavior often indicates defense evasion tactics employed by attackers to conceal malicious operations by removing artifacts immediately after execution, which can expose systems to unauthorized access, tampering, or persistence mechanisms if not properly mitigated.

More Information

Information

Description: Binary executed and self-deleted Category: Defense Evasion Method: Indicator Removal on Host Importance: Critical

Analysis of the Event

The binary_self_deletion detection, flagged by Jibril, highlights a critical defense evasion method where a binary executes and then self-deletes. This behavior is particularly concerning as it indicates an attempt to erase traces of execution, thereby hindering forensic analysis and post-incident investigation efforts.

From a security perspective, this tactic aligns with the MITRE ATT&CK framework's defense evasion techniques under T1070 (Indicator Removal on Host). Such methods are often employed by attackers to execute malicious payloads that operate only in memory, leaving no trace on disk. This approach makes detection by traditional file-based antivirus solutions challenging and can facilitate advanced persistent threats (APTs).

In legitimate workflows, temporary file creation and deletion may occur, especially in high-performance or ephemeral environments such as containerized applications. However, the deliberate unlinking of an executed binary requires careful scrutiny, particularly in CI/CD pipelines where trust boundaries are critical.

Implications

Implications for CI/CD Pipelines

The detection of this behavior during a CI/CD pipeline run indicates a potential risk introduced by recent code changes. If left unchecked, merging such changes into production could result in malicious artifacts operating covertly within the infrastructure, bypassing detection mechanisms. This may lead to significant consequences, including data breaches, privilege escalation, and unauthorized persistence within the system. The detection emphasizes the need for stringent controls and monitoring in CI/CD environments to mitigate risks associated with transient binaries.

Implications for Staging

In staging environments, adversarial testing can reveal vulnerabilities that might be exploited by attackers. Data leakage from staging environments could lead to insider threats or unauthorized access before production deployment. Detecting binary self-deletion is crucial as it may indicate the presence of malicious actors who are attempting to evade detection and maintain persistence across different stages of the development lifecycle.

Implications for Production

In a production environment, the long-term persistence risks associated with binary self-deletion include lateral movement within the network, credential theft, data exfiltration, and APTs. Attackers may use this technique to deploy malware that operates only in memory, leaving no trace on disk and making detection by traditional file-based antivirus solutions challenging. This can lead to sustained access to critical systems and sensitive information.

Recommended Actions

Actions for CI/CD Pipelines

1. Review Recent Code Changes: Immediately review all recent commits and merge requests for any unusual or unauthorized modifications that could introduce self-deleting binaries.

2. Enhance Monitoring and Logging: Implement or enhance logging of all file operations, especially execution and deletion events, to help trace the origin of such behaviors.

3. Conduct a Security Audit: Perform a thorough security audit of your CI/CD pipeline to ensure there are no vulnerabilities that could be exploited to introduce malicious code.

4. Update Security Policies: Revise and strengthen security policies and access controls to limit who can push code changes and under what conditions.

Actions for Staging

1. Perform In-depth Forensic Analysis: Conduct a detailed forensic analysis to understand the source and intent of the self-deleting binaries.

2. Isolate Affected Systems: Immediately isolate systems where the binary self-deletion was detected to prevent potential spread or escalation.

3. Verify Integrity of Staging Data: Ensure that all data in the staging environment is intact and has not been tampered with or exfiltrated.

4. Strengthen Staging Environment Security: Implement stricter security measures in the staging environment, including more rigorous monitoring and access controls.

Actions for Production

1. Immediate Incident Response: Initiate an incident response protocol to assess the impact and scope of the issue. This includes isolating affected systems and conducting a thorough investigation.

2. Notify Relevant Stakeholders: Inform IT security teams, management, and potentially affected clients or partners about the breach to maintain transparency and trust.

3. Restore from Known Good Backups: If malicious activity is confirmed, restore affected systems from backups that are verified to be free of the malicious binaries.

4. Continuous Monitoring and Improvement: After addressing the immediate threat, implement continuous monitoring solutions to detect similar threats in the future and continuously improve defense mechanisms based on the latest threat intelligence.