CVE-2010-1322 in Kerberos
Summary
by MITRE
The merge_authdata function in kdc_authdata.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) 1.8.x before 1.8.4 does not properly manage an index into an authorization-data list, which allows remote attackers to cause a denial of service (daemon crash), or possibly obtain sensitive information, spoof authorization, or execute arbitrary code, via a TGS request that triggers an uninitialized pointer dereference, as demonstrated by a request from a Windows Active Directory client.
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Analysis
by VulDB Data Team • 09/26/2021
The vulnerability described in CVE-2010-1322 represents a critical flaw in the Key Distribution Center implementation of MIT Kerberos 5 version 1.8.x prior to 1.8.4. This issue resides within the merge_authdata function located in kdc_authdata.c, which serves as a core component responsible for processing authorization data during ticket granting service operations. The flaw manifests as improper index management within an authorization-data list structure, creating a scenario where an attacker can manipulate the flow of data processing to trigger unintended behavior in the Kerberos daemon.
The technical implementation of this vulnerability stems from a classic buffer management error where an uninitialized pointer is dereferenced during the processing of TGS (Ticket Granting Service) requests. When a Windows Active Directory client submits a specially crafted request to the KDC, the merge_authdata function fails to properly validate or initialize the index variable used to traverse the authorization-data list. This condition creates a path where the daemon attempts to access memory locations that have not been properly allocated or initialized, resulting in either a segmentation fault causing daemon crash or potentially allowing for memory corruption that could be exploited for more severe attacks.
The operational impact of this vulnerability extends beyond simple denial of service, as it presents multiple attack vectors that could compromise system security. Remote attackers can leverage this flaw to cause daemon crashes, effectively disrupting authentication services and creating availability issues for legitimate users. More concerning is the potential for information disclosure where uninitialized memory contents might be exposed through the improper data handling. The vulnerability also opens possibilities for authorization spoofing, where attackers might manipulate the authorization data processing to gain unauthorized access privileges, and in the most severe cases, arbitrary code execution could occur if the memory corruption allows for code injection techniques. This represents a significant threat to enterprise environments heavily dependent on Kerberos authentication mechanisms.
Mitigation strategies for this vulnerability require immediate patching of affected MIT Kerberos 5 installations to version 1.8.4 or later, which contains the necessary fixes for proper index management and pointer initialization. System administrators should also implement monitoring for unusual TGS request patterns that might indicate exploitation attempts, as well as ensure proper network segmentation to limit exposure of Kerberos services to untrusted networks. The vulnerability aligns with CWE-476, which describes NULL pointer dereference conditions, and maps to ATT&CK technique T1550.003 for use of Kerberos authentication services. Organizations should also consider implementing additional authentication layers and access controls to reduce the impact should exploitation occur, while maintaining comprehensive audit logging of authentication service operations to detect potential abuse of this vulnerability in production environments.