CVE-2008-1658 in PolicyKit
Summary
by MITRE
Format string vulnerability in the grant helper (polkit-grant-helper.c) in PolicyKit 0.7 and earlier allows attackers to cause a denial of service (crash) and possibly execute arbitrary code via format strings in a password.
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Analysis
by VulDB Data Team • 07/31/2021
The vulnerability identified as CVE-2008-1658 represents a critical format string flaw within PolicyKit's grant helper component, specifically in the polkit-grant-helper.c file version 0.7 and earlier. This issue affects the system-level authorization framework that governs user permissions and access controls in Unix-like operating systems. The vulnerability stems from improper input validation within the authentication processing pipeline where user-provided password data is directly used in format string operations without adequate sanitization. The flaw exists in the interaction between the PolicyKit daemon and its helper utilities, creating a path for malicious input to be interpreted as format specifiers rather than plain text.
The technical exploitation of this vulnerability occurs when an attacker provides specially crafted password input containing format string specifiers such as %s, %d, or %x to the grant helper process. When the system processes this input through insecure printf-like functions, the format string specifiers are interpreted by the program's memory management system, leading to potential stack corruption and arbitrary code execution. This type of vulnerability maps directly to CWE-134, which specifically addresses the use of untrusted format strings in applications. The attack vector is particularly dangerous because it can be leveraged both for denial of service through process crashes and for privilege escalation to execute arbitrary code with elevated system privileges.
The operational impact of this vulnerability extends beyond simple system instability, as it provides attackers with potential pathways to compromise entire system authorization frameworks. When exploited successfully, the vulnerability allows attackers to bypass authentication mechanisms that PolicyKit is designed to enforce, potentially enabling unauthorized access to system resources and services. The grant helper component typically runs with elevated privileges to perform administrative tasks, making successful exploitation particularly dangerous. From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1068, which involves the exploitation of legitimate credentials and privileges for system compromise. The vulnerability also intersects with T1059, representing a potential code execution vector through command injection in the authentication context.
Mitigation strategies for CVE-2008-1658 must address both immediate remediation and long-term security posture improvements. The primary solution involves upgrading to PolicyKit versions 0.8 or later where the format string vulnerability has been eliminated through proper input sanitization and the implementation of secure string formatting functions. System administrators should also implement strict input validation policies for all authentication components and consider deploying intrusion detection systems to monitor for suspicious authentication attempts. Additional protective measures include implementing mandatory access controls, regular security auditing of system components, and ensuring that privilege separation mechanisms are properly enforced. Organizations should also conduct comprehensive vulnerability assessments to identify other components that might be susceptible to similar format string vulnerabilities, particularly in legacy systems that have not received regular security updates. The remediation process should include thorough testing of updated systems to ensure that the security patches do not introduce regressions in functionality while maintaining the integrity of the authorization framework.