CVE-2005-2500 in Linux
Summary
by MITRE
Buffer overflow in the xdr_xcode_array2 function in xdr.c in Linux kernel 2.6.12, as used in SuSE Linux Enterprise Server 9, might allow remote attackers to cause a denial of service and possibly execute arbitrary code via crafted XDR data for the nfsacl protocol.
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Analysis
by VulDB Data Team • 07/04/2019
The vulnerability identified as CVE-2005-2500 represents a critical buffer overflow flaw within the Linux kernel's Network File System Access Control List implementation. This issue specifically affects the xdr_xcode_array2 function located in the xdr.c file of kernel version 2.6.12, which is utilized by SuSE Linux Enterprise Server 9. The flaw manifests when processing crafted XDR (External Data Representation) data packets specifically designed for the nfsacl protocol, creating a potential attack vector that could be exploited by remote adversaries.
The technical nature of this vulnerability stems from inadequate bounds checking within the xdr_xcode_array2 function, which handles the encoding and decoding of array data structures in the XDR protocol. When the function processes malformed XDR data containing oversized array specifications, it fails to properly validate the incoming data length against allocated buffer boundaries. This allows attackers to write beyond the intended memory allocation, potentially overwriting adjacent memory locations and corrupting critical kernel data structures. The vulnerability operates at the kernel level, making it particularly dangerous as it can be exploited to gain elevated privileges or cause system instability.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enabling remote code execution. Attackers exploiting this flaw could craft malicious XDR packets that, when processed by the NFS ACL service, trigger the buffer overflow condition. This could result in system crashes, kernel panics, or more severe consequences including privilege escalation to root access. The attack surface is significant as NFS services are commonly exposed across network boundaries, making this vulnerability particularly attractive to threat actors seeking to compromise enterprise systems. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of improper input validation in kernel space code.
Mitigation strategies for CVE-2005-2500 should prioritize immediate patching of affected systems with updated kernel versions that contain proper bounds checking implementations. Organizations should also implement network segmentation to limit exposure of NFS services to trusted networks only, and consider disabling unnecessary NFS ACL functionality where possible. Monitoring for unusual XDR traffic patterns and implementing intrusion detection systems can help identify potential exploitation attempts. The ATT&CK framework categorizes this vulnerability under privilege escalation and denial of service techniques, with the exploitation requiring network access and potentially elevated privileges depending on the specific attack vector employed. System administrators should also conduct comprehensive security assessments to identify all instances of affected kernel versions and ensure complete remediation across their infrastructure.