CVE-2001-0417 in Kerberos
Summary
by MITRE
Kerberos 4 (aka krb4) allows local users to overwrite arbitrary files via a symlink attack on new ticket files.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 05/31/2018
The vulnerability identified as CVE-2001-0417 represents a critical security flaw within the Kerberos 4 authentication system that has significant implications for local system integrity. This issue affects the Kerberos version 4 implementation and specifically targets the ticket file creation process that occurs during authentication operations. The vulnerability stems from insufficient validation of temporary file creation mechanisms within the Kerberos 4 framework, creating an environment where malicious local users can exploit symlink attacks to gain unauthorized access to system resources.
The technical flaw manifests when Kerberos 4 creates new ticket files during authentication processes. The implementation fails to properly verify the existence and ownership of target file paths before creating new ticket files, allowing local attackers to establish symbolic links in strategic locations. When the authentication process attempts to create a ticket file at a path controlled by a symlink, the system writes data to the target of the symlink rather than the intended location. This fundamental race condition vulnerability enables attackers to overwrite arbitrary files on the system with data controlled by the attacker, potentially compromising system security and integrity.
The operational impact of this vulnerability extends beyond simple file overwriting capabilities, as it provides attackers with a mechanism to manipulate critical system files and potentially escalate privileges. Local users can leverage this vulnerability to overwrite configuration files, system binaries, or other sensitive data structures within the Kerberos environment. The attack vector requires local system access but does not necessitate network connectivity or specialized privileges, making it particularly dangerous in multi-user environments where privilege separation is crucial. The vulnerability affects systems running Kerberos 4 implementations where ticket files are created with predictable paths and insufficient security controls.
Mitigation strategies for CVE-2001-0417 require immediate implementation of file system security measures and process hardening techniques. System administrators should ensure that ticket file creation processes validate file paths and implement proper atomic file creation mechanisms that prevent symbolic link manipulation. The recommended approach involves using secure file creation patterns that utilize file descriptor operations with appropriate permissions and file system atomicity guarantees. Additionally, implementing proper access controls and monitoring for unauthorized file modifications can help detect exploitation attempts. This vulnerability aligns with CWE-377, which addresses insecure temporary file creation, and corresponds to ATT&CK technique T1059.001 for command and scripting interpreter usage in privilege escalation scenarios. Organizations should consider migrating to modern Kerberos implementations such as Kerberos 5 that address these fundamental security flaws through improved file handling and process isolation mechanisms.