CVE-2009-5153 in NetWare
Summary
by MITRE
In Novell NetWare before 6.5 SP8, a stack buffer overflow in processing of CALLIT RPC calls in the NFS Portmapper daemon in PKERNEL.NLM allowed remote unauthenticated attackers to execute code, because a length field was incorrectly trusted.
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Analysis
by VulDB Data Team • 04/14/2020
The vulnerability identified as CVE-2009-5153 represents a critical stack buffer overflow flaw within Novell NetWare's NFS Portmapper daemon component known as PKERNEL.NLM. This issue affects Novell NetWare versions prior to 6.5 Service Pack 8, creating a significant security risk that could be exploited by remote attackers without authentication. The vulnerability specifically manifests during the processing of CALLIT RPC calls, which are fundamental operations within the Network File System implementation that allows clients to access files across a network.
The technical root cause of this vulnerability stems from improper validation of input parameters within the RPC processing pipeline. When the NFS Portmapper daemon receives a CALLIT RPC request, it fails to properly validate the length field associated with the incoming data structure before using this information to allocate stack space for buffer operations. This trust-based approach to input validation creates an exploitable condition where an attacker can craft a malicious RPC call with an oversized length field, causing the application to write beyond the bounds of allocated stack memory. The flaw aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of insecure input handling that violates fundamental security principles.
The operational impact of this vulnerability extends beyond simple code execution capabilities, as it provides attackers with the ability to gain unauthorized access to systems running vulnerable NetWare versions. Remote unauthenticated exploitation means that attackers do not require valid credentials or network proximity to exploit the vulnerability, making it particularly dangerous in enterprise environments where network services are exposed to external networks. Successful exploitation could result in complete system compromise, allowing attackers to execute arbitrary code with the privileges of the affected service process. This vulnerability directly maps to ATT&CK technique T1203, which covers the exploitation of remote services for code execution, and represents a significant threat to network infrastructure security.
Mitigation strategies for CVE-2009-5153 primarily focus on immediate patch management and system hardening measures. Organizations should prioritize upgrading to Novell NetWare 6.5 SP8 or later versions that contain the necessary security fixes for this vulnerability. Additionally, network segmentation and firewall rules should be implemented to restrict access to NFS services and RPC endpoints, particularly when these services are running on systems that cannot be immediately patched. System administrators should also consider disabling unnecessary network services and implementing monitoring solutions to detect anomalous RPC call patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and the potential consequences of trusting unvalidated length fields in network service implementations, reinforcing industry best practices for secure coding and defensive security measures.