CVE-2011-0285 in Kerberos
Summary
by MITRE
The process_chpw_request function in schpw.c in the password-changing functionality in kadmind in MIT Kerberos 5 (aka krb5) 1.7 through 1.9 frees an invalid pointer, which allows remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via a crafted request that triggers an error condition.
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Analysis
by VulDB Data Team • 01/19/2025
The vulnerability described in CVE-2011-0285 resides within the Kerberos 5 authentication system, specifically in the kadmind daemon component responsible for handling password changes. This flaw exists in versions 1.7 through 1.9 of the MIT Kerberos 5 implementation, making it a significant security concern for organizations relying on Kerberos-based authentication. The vulnerability manifests in the process_chpw_request function located in the schpw.c file, which governs the password change functionality. The core issue stems from improper memory management practices where the function attempts to free an invalid pointer during error handling scenarios, creating a potential exploitation vector for remote attackers.
The technical nature of this vulnerability aligns with CWE-415, which describes double free errors and improper pointer management in memory handling. When a malformed password change request is sent to the kadmind daemon, it triggers an error condition that causes the process_chpw_request function to attempt freeing memory that has already been released or was never properly allocated. This invalid pointer dereference creates a memory corruption condition that can be exploited to execute arbitrary code on the target system or cause the daemon to crash completely. The vulnerability operates at the application level within the Kerberos administration service, making it particularly dangerous as it can be triggered remotely without requiring authentication.
The operational impact of this vulnerability extends beyond simple denial of service, as remote code execution capabilities could allow attackers to gain unauthorized access to the Kerberos infrastructure. Organizations using affected versions of MIT Kerberos 5 face potential compromise of their authentication systems, which could lead to broader security breaches throughout their network environments. The daemon crash scenario represents a denial of service condition that would prevent legitimate users from changing their passwords, disrupting normal authentication workflows and potentially leading to account lockout situations. This vulnerability particularly affects environments where kadmind is exposed to untrusted networks or where password change functionality is accessible over network connections.
Mitigation strategies for CVE-2011-0285 should prioritize immediate patching of affected systems to the latest stable versions of MIT Kerberos 5 where this memory management issue has been resolved. System administrators should also implement network segmentation to limit exposure of kadmind services to trusted networks only, reducing the attack surface for remote exploitation attempts. Additional protective measures include monitoring for unusual password change requests and implementing intrusion detection systems that can identify malformed Kerberos traffic patterns. The vulnerability demonstrates the critical importance of proper memory management in security-critical applications and highlights the need for thorough code review processes, particularly around error handling and resource cleanup operations. Organizations should also consider implementing automated patch management systems to ensure timely deployment of security updates across all Kerberos implementations within their infrastructure.