CVE-2014-4345 in Communications WebRTC Session Controller
Summary
by MITRE
Off-by-one error in the krb5_encode_krbsecretkey function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c in the LDAP KDB module in kadmind in MIT Kerberos 5 (aka krb5) 1.6.x through 1.11.x before 1.11.6 and 1.12.x before 1.12.2 allows remote authenticated users to cause a denial of service (buffer overflow) or possibly execute arbitrary code via a series of "cpw -keepold" commands.
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Analysis
by VulDB Data Team • 01/04/2023
The CVE-2014-4345 vulnerability represents a critical off-by-one error within the LDAP Key Distribution Center (KDB) module of MIT Kerberos 5 implementations. This flaw specifically affects the krb5_encode_krbsecretkey function located in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c, which is responsible for encoding secret keys when processing principal data within LDAP directories. The vulnerability exists in versions 1.6.x through 1.11.x before 1.11.6 and 1.12.x before 1.12.2, making it a long-standing issue that affected numerous production deployments of Kerberos authentication systems. The flaw manifests when authenticated remote attackers exploit the function through a sequence of "cpw -keepold" commands, which are used to change passwords while maintaining old credentials.
The technical implementation of this vulnerability stems from improper bounds checking in the krb5_encode_krbsecretkey function where the buffer allocation does not account for the null terminator character required for string operations. When processing principal data, the function fails to properly calculate the required buffer size, leading to an off-by-one condition that can result in memory corruption. This type of error falls under CWE-129, which specifically addresses improper validation of array indices, and more broadly under CWE-787, concerning out-of-bounds write operations. The vulnerability allows attackers to manipulate the buffer boundaries through crafted input sequences, potentially causing memory corruption that can lead to arbitrary code execution or denial of service conditions.
The operational impact of CVE-2014-4345 extends significantly beyond simple service disruption, as it provides attackers with potential paths to privilege escalation and system compromise within Kerberos environments. Since the vulnerability requires only authenticated access, it can be exploited by users who have legitimate Kerberos credentials but lack administrative privileges. The attack vector through "cpw -keepold" commands means that any user with access to the kadmind service can potentially trigger the buffer overflow, making it particularly dangerous in environments where user access controls are not strictly enforced. The vulnerability's potential for arbitrary code execution places it in the ATT&CK matrix under T1059.007 for command and scripting interpreter, and T1499.004 for network denial of service, while also supporting T1068 for exploit for privilege escalation. Organizations running affected Kerberos versions face significant risk as attackers could leverage this vulnerability to gain unauthorized access to authentication services, potentially compromising entire authentication domains.
Mitigation strategies for CVE-2014-4345 require immediate patching of affected systems to versions 1.11.6 or 1.12.2, which contain the necessary fixes for the buffer overflow condition. System administrators should also implement network segmentation and access controls to limit exposure of kadmind services to untrusted networks, as the vulnerability requires network access to the Kerberos administration service. Monitoring for suspicious "cpw -keepold" command usage patterns can help detect potential exploitation attempts, while implementing intrusion detection systems that can identify anomalous authentication behavior. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all systems running affected Kerberos versions and ensure that proper patch management processes are in place to prevent similar issues in the future. The fix implemented in the patched versions addresses the specific bounds checking error by properly calculating buffer sizes and ensuring that all string operations include adequate space for null terminators, thereby preventing the off-by-one condition that enabled the exploit.