CVE-2007-0557 in rMake
Summary
by MITRE
rMake before 1.0.4 drops root privileges in a way that retains the original supplemental groups, which might allow attackers to gain privileges via a crafted recipe file, a different vulnerability than CVE-2007-0536.
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Analysis
by VulDB Data Team • 08/18/2018
The vulnerability identified as CVE-2007-0557 affects rMake versions prior to 1.0.4 and represents a privilege escalation issue stemming from improper privilege management during the execution of recipe files. This flaw occurs when the rMake utility drops root privileges but fails to properly reset the supplemental groups associated with the original root user context. The vulnerability is distinct from CVE-2007-0536 and demonstrates a critical flaw in Unix-like privilege separation mechanisms where the system retains group memberships that should be discarded during privilege reduction. The core issue lies in the improper handling of group identifiers during the privilege dropping process, creating a persistent security boundary violation that attackers can exploit.
The technical implementation of this vulnerability exploits the fundamental principle of Unix privilege management where processes running with elevated privileges must properly relinquish all unnecessary permissions before dropping to a lower privilege level. When rMake executes a recipe file, it initially runs with root privileges to perform system-level operations such as file manipulation, package installation, and configuration changes. However, during the privilege dropping phase, the system correctly switches the user ID but retains the original process's supplemental groups, which often include administrative group memberships such as wheel, admin, or other privileged group identifiers. This retention allows an attacker who can control a recipe file to leverage these retained group memberships to perform operations that should require root access but are now possible through the compromised group permissions.
The operational impact of CVE-2007-0557 extends beyond simple privilege escalation to encompass potential system compromise and data integrity violations. Attackers can craft malicious recipe files that exploit the retained group memberships to access restricted system resources, modify critical configuration files, or execute commands with elevated privileges that would normally be restricted. This vulnerability particularly affects systems where rMake is used for package management or automated system configuration, as these environments often involve executing untrusted recipe content with root privileges. The flaw creates a persistent backdoor mechanism where attackers can maintain elevated access through the compromised group memberships, potentially leading to complete system compromise and persistent access.
Security mitigation strategies for CVE-2007-0557 require immediate patching of rMake to version 1.0.4 or later, which properly implements privilege dropping by clearing all supplemental groups during the privilege reduction process. Organizations should also implement strict access controls over recipe files and ensure that only trusted users can create or modify recipe content. System administrators should monitor for unauthorized recipe file modifications and implement file integrity monitoring solutions to detect potential exploitation attempts. Additionally, the vulnerability aligns with CWE-250 Improper Privilege Management and follows ATT&CK technique T1068 Privilege Escalation through group membership retention, making it a critical target for security hardening measures. The fix implemented in rMake 1.0.4 specifically addresses the group ID handling by ensuring that all supplemental groups are properly cleared when dropping root privileges, preventing attackers from leveraging these retained permissions to escalate privileges through crafted recipe files.