Exec From Unusual Dir

Quick Explanation

The exec_from_unusual_dir event identifies the execution of files from non-standard directories like /tmp, /dev, /sys, /proc, and others. This behavior is typically indicative of malicious activities, such as running unauthorized code or exploiting system vulnerabilities. Detection of this activity can signal potential threats to both build and production environments, compromising their integrity.

Information

Description: Execution from unusual directory Category: Execution Method: User Execution Importance: High, Critical

Analysis of the Event

The exec_from_unusual_dir detection event is triggered when files are executed from directories that are not conventionally used for executing binaries or scripts. Such activities can be symptomatic of various adversarial tactics and techniques detailed in frameworks like MITRE ATT&CK.

For example, attackers may use DNS tunneling to establish a covert channel through which they execute code from temporary directories such as /tmp (T1048). They might also leverage the system's inherent permissions to execute scripts or binaries from privileged directories like /dev and /proc, which can lead to privilege escalation (T1548.002) or persistence mechanisms (T1136).

Implications

Implications for CI/CD Pipelines

In the context of CI/CD pipelines, execution from unusual directories can indicate several risks:

• Build Process Compromise: Malicious actors might inject code into build processes through compromised dependencies or scripts executed from temporary directories.

• Dependency Poisoning: Adversaries could exploit vulnerabilities in third-party libraries by executing malicious payloads from non-standard locations.

• Artifact Integrity: The integrity of build artifacts can be compromised if unauthorized code execution is allowed, leading to potential security breaches once deployed.

Implications for Staging

In the staging environment:

• Adversarial Testing: Attackers may use staging environments to test their exploits before targeting production systems. Executing from unusual directories in this phase can indicate early-stage adversarial activities.

• Data Leakage: Unauthorized access through execution of scripts or binaries from temporary or system-critical directories could lead to data leakage, especially if sensitive information is processed during testing phases.

• Insider Threats: Insiders with elevated privileges might misuse their access by executing unauthorized code, posing significant risks.

Implications for Production

For production environments:

• Long-term Persistence Risks: Adversaries can establish long-term persistence mechanisms by executing malicious payloads from temporary or system directories, ensuring continued control over the infrastructure.

• Lateral Movement: Once an initial foothold is established through unusual directory execution, attackers may perform lateral movements to access other critical systems.

• Credential Theft and Data Exfiltration: Execution from non-standard locations can enable credential theft and subsequent data exfiltration attempts, leading to significant breaches.

• Advanced Persistent Threats (APT): APT groups often employ sophisticated techniques to maintain persistent access by executing malicious code from unexpected directories.

Recommended Actions

Actions for CI/CD Pipelines

1. Review and Audit Build Scripts: Examine all build scripts and the execution paths they use. Ensure that scripts do not pull code from or execute binaries in non-standard directories like /tmp or /dev.

2. Validate Third-party Dependencies: Regularly scan and validate third-party libraries and dependencies for integrity and authenticity. Ensure they are sourced from trusted repositories.

3. Security Training for Developers: Educate developers about the risks associated with executing files from unusual directories and the importance of using standard, secure directories for all operations.

Actions for Staging

1. Conduct Regular Security Audits: Periodically audit the staging environment to detect and mitigate unauthorized executions from non-standard directories.

2. Implement Strict Access Controls: Restrict access to critical system directories and ensure that only authorized personnel can deploy or execute scripts and binaries.

3. Simulate Attack Scenarios: Regularly perform red team exercises to test the resilience of the staging environment against attacks involving unusual execution paths.

4. Enhance Anomaly Detection: Use advanced anomaly detection tools to identify deviations from normal execution patterns, particularly executions from unusual directories.

Actions for Production

1. Harden System Directories: Apply strict permissions and access controls on system directories like /tmp, /dev, /sys, and /proc to prevent unauthorized access and execution.

2. Regular Security Assessments: Conduct comprehensive security assessments to identify and mitigate risks associated with unusual executions, focusing on potential persistence mechanisms and lateral movements.

3. Update and Patch Systems: Keep all systems updated and patched to reduce vulnerabilities that could be exploited through executions from unusual directories.