CVE-2007-3912 in debian-goodies
Summary
by MITRE
checkrestart in debian-goodies before 0.34 allows local users to gain privileges via shell metacharacters in the name of the executable file for a running process.
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Analysis
by VulDB Data Team • 07/30/2019
The vulnerability identified as CVE-2007-3912 affects the checkrestart utility within debian-goodies package version 0.34 and earlier. This tool is designed to identify running processes that may need restarting after package upgrades, particularly when shared libraries have been updated. The flaw resides in how checkrestart handles executable names when processing running processes, creating a potential privilege escalation vector for local attackers. The vulnerability specifically exploits the lack of proper input sanitization when the utility encounters shell metacharacters within executable file names.
The technical implementation of this vulnerability stems from improper handling of command execution within the checkrestart utility. When the tool enumerates running processes and attempts to determine which ones require restarting, it fails to properly escape or sanitize shell metacharacters present in executable names. This occurs during the construction of shell commands that are subsequently executed to gather information about processes. Attackers can manipulate process names to contain characters such as semicolons, ampersands, or backticks that are interpreted by the shell, allowing arbitrary command execution with elevated privileges. The vulnerability essentially represents a classic command injection flaw where user-controllable input directly influences shell command construction without adequate sanitization.
The operational impact of this vulnerability is significant for systems running affected versions of debian-goodies, as it provides local attackers with a means to escalate privileges from their current user context to root level access. Since checkrestart is typically installed with appropriate permissions to access system process information and may be executed with elevated privileges during package management operations, the attack surface extends beyond simple local privilege escalation to potentially compromise entire system integrity. The vulnerability can be exploited by any local user who can create or manipulate processes with specific naming patterns containing shell metacharacters, making it particularly dangerous in multi-user environments where privilege separation is expected.
This vulnerability maps to CWE-78, which specifically addresses Improper Neutralization of Special Elements used in OS Commands, and aligns with ATT&CK technique T1068, which covers Exploitation for Privilege Escalation. The attack requires minimal prerequisites beyond local system access and knowledge of process naming patterns that can trigger shell metacharacter interpretation. Mitigation strategies include upgrading to debian-goodies version 0.34 or later where proper input sanitization has been implemented, implementing strict process name validation, and ensuring that system utilities properly escape shell metacharacters when constructing commands. Additionally, system administrators should consider restricting access to the checkrestart utility and monitoring for unusual process naming patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of input validation in system utilities that interact with shell commands, particularly in privileged contexts where the consequences of command injection can be severe.