CVE-2023-28487 in sudo
Summary
by MITRE • 03/16/2023
Sudo before 1.9.13 does not escape control characters in sudoreplay output.
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Analysis
by VulDB Data Team • 05/21/2025
The vulnerability identified as CVE-2023-28487 affects the sudo command utility version 1.9.12 and earlier, specifically within the sudoreplay functionality. This issue arises from insufficient sanitization of control characters in the output generated by sudoreplay, which is designed to replay sudo command sessions for auditing and forensic purposes. The flaw exists in how the system handles terminal control sequences and special characters during session replay operations, creating potential security implications for environments relying on sudo audit trails.
Control characters in terminal environments include escape sequences, backspaces, carriage returns, and other non-printable ASCII values that can manipulate terminal display behavior. When sudoreplay processes session recordings, it fails to properly escape or filter these characters before outputting them to the terminal or log files. This oversight allows malicious actors who have access to sudo session recordings to potentially inject terminal control sequences that could alter the display of the replay output, conceal malicious activities, or manipulate the terminal environment during playback.
The operational impact of this vulnerability extends beyond simple display issues, as it can compromise the integrity of audit trails that security teams rely upon for monitoring privileged activities. When terminal control characters are not properly escaped, attackers could craft session recordings that appear legitimate while actually concealing malicious operations. This creates a significant risk for security monitoring systems that depend on accurate sudo session replay data for detecting unauthorized activities or policy violations. The vulnerability particularly affects environments where sudo sessions are recorded for compliance auditing, forensic investigations, or security monitoring purposes.
Organizations using sudo versions prior to 1.9.13 should prioritize immediate patching to address this vulnerability. The fix implemented in sudo 1.9.13 involves proper escaping of control characters in sudoreplay output, ensuring that terminal manipulation sequences are rendered harmless during session playback. This remediation aligns with security best practices for output sanitization and follows principles outlined in CWE-117, which addresses improper output neutralization for logs and other security-relevant outputs. The vulnerability also relates to ATT&CK technique T1562.006, which covers "Impair Command History Logging", as it could potentially allow adversaries to manipulate or obscure audit trail information that would otherwise be available for detection and analysis.
Security teams should implement additional monitoring for sudo session replay activities and ensure that audit logs are properly configured to detect anomalous terminal behavior. The vulnerability demonstrates the importance of proper input and output sanitization in security-critical applications, particularly those handling privileged command sequences and audit data. Organizations should also review their sudo configuration policies and ensure that session recording is properly secured and that access controls are maintained for replay functionality. This issue underscores the broader principle that even seemingly benign security tools can introduce vulnerabilities when proper sanitization controls are not implemented in all output pathways.