CVE-2022-2068 c_rehash Command Injection Vulnerability

CVE-2022-2068 describes a command injection vulnerability present within the c_rehash script. This script is often used to update certificate symlinks. Successful exploitation of this vulnerability can lead to arbitrary code execution on the target system. While the Microsoft Security Response Center (MSRC) has published information regarding this vulnerability, the specifics of affected products and exploitation details require further investigation and are not explicitly detailed in the provided source. Defenders must prioritize identifying and mitigating potential attack vectors related to this vulnerability to prevent system compromise. Given the nature of command injection vulnerabilities, the impact can be severe, ranging from data theft to complete system takeover.

Attack Chain

1. Attacker gains initial access to a system where the c_rehash script is accessible and executable. This could involve techniques like exploiting a separate web application vulnerability, or through compromised credentials.
2. The attacker crafts a malicious certificate file or modifies an existing one to include command injection payloads within the certificate’s subject or other relevant fields.
3. The attacker executes the c_rehash script, pointing it towards the directory containing the malicious certificate.
4. During execution, the c_rehash script parses the certificate, unknowingly extracting the malicious payload embedded within the certificate’s fields.
5. The script then attempts to use the extracted payload as part of a command, due to the lack of proper sanitization or validation of the input.
6. The injected command is executed with the privileges of the user running the c_rehash script, potentially leading to arbitrary code execution.
7. The attacker leverages the code execution to install malware, establish persistence, or escalate privileges.
8. The attacker achieves their final objective, such as data exfiltration, system disruption, or lateral movement within the network.

Impact

Successful exploitation of CVE-2022-2068 allows attackers to execute arbitrary commands on a vulnerable system. The impact can range from data theft and malware installation to complete system compromise and lateral movement within the network. This vulnerability poses a significant risk to organizations that rely on the c_rehash script for managing certificates. The lack of specific victim counts or sector targeting information in the provided source highlights the need for proactive detection and mitigation efforts across all potentially affected environments.

Recommendation

• Monitor process executions for instances of the c_rehash script executing with unusual or suspicious command-line arguments. Deploy the provided Sigma rule (c_rehash_command_injection) to detect this behavior.
• Implement input validation and sanitization measures for all certificate-related operations, particularly when using scripts like c_rehash.
• Investigate systems where the c_rehash script is used to identify potential exploitation attempts related to CVE-2022-2068.
• Monitor file system events for the creation or modification of certificates containing suspicious payloads, as these may be used in conjunction with the vulnerability. Deploy the provided Sigma rule (suspicious_certificate_creation) to detect such activity.
• Regularly review and update certificate management procedures to ensure they align with security best practices and mitigate potential vulnerabilities.