CVE-2008-0639 in Novell
Summary
by MITRE
Stack-based buffer overflow in the EnumPrinters function in the Spooler service (nwspool.dll) in Novell Client 4.91 SP2, SP3, and SP4 for Windows allows remote attackers to execute arbitrary code via a crafted RPC request, aka Novell bug 353138, a different vulnerability than CVE-2006-5854. NOTE: this issue exists because of an incomplete fix for CVE-2007-6701.
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Analysis
by VulDB Data Team • 08/06/2019
The vulnerability described in CVE-2008-0639 represents a critical stack-based buffer overflow flaw within the Novell Client 4.91 software suite, specifically affecting the Spooler service component known as nwspool.dll. This issue manifests in the EnumPrinters function which handles printer enumeration requests through Remote Procedure Call mechanisms, creating a pathway for remote code execution attacks. The vulnerability affects multiple service pack versions including SP2, SP3, and SP4, indicating it persisted across several updates and patches, highlighting the complexity of addressing such flaws in enterprise software environments.
The technical implementation of this vulnerability stems from inadequate input validation within the nwspool.dll library where the EnumPrinters function fails to properly bounds-check data received through RPC communications. When a maliciously crafted RPC request is sent to a vulnerable Novell Client system, the function processes the malformed input without sufficient safeguards, causing a buffer overflow that can overwrite adjacent memory locations including return addresses and control data. This particular flaw falls under the Common Weakness Enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite stack memory and potentially execute arbitrary code.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential lateral movement within network environments. Attackers exploiting this vulnerability can gain unauthorized access to systems running vulnerable Novell Client versions, potentially escalating privileges and establishing persistent access points. The remote nature of the attack means that exploitation can occur without physical access to the target system, making it particularly dangerous in enterprise environments where network printers are commonly accessible across multiple network segments. This vulnerability directly aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, as successful exploitation would enable attackers to execute arbitrary commands on compromised systems.
The persistence of this vulnerability despite previous patches indicates a fundamental flaw in the software development lifecycle or patch management process, as it represents an incomplete fix for CVE-2007-6701. This pattern of remediation failure suggests that organizations running affected Novell Client versions face continued risk of exploitation, particularly in environments where patch deployment may be delayed or incomplete. The vulnerability demonstrates the importance of comprehensive testing of security patches and the potential for new vulnerabilities to emerge from attempted fixes for existing issues. Organizations should implement immediate mitigation strategies including network segmentation, RPC port filtering, and deployment of official patches from Novell to address this critical security gap in their print management infrastructure.
The broader implications of this vulnerability extend to enterprise security posture, as printer services often serve as entry points for attackers seeking to establish footholds within larger network environments. The Spooler service typically runs with elevated privileges and maintains persistent network connections, making it an attractive target for attackers seeking to maintain long-term access to compromised systems. This vulnerability underscores the need for comprehensive security assessments of all network services and the critical importance of maintaining current security patches across all enterprise software components, particularly those with remote access capabilities.