CVE-2013-0085 in SharePoint Server
Summary
by MITRE
Buffer overflow in Microsoft SharePoint Server 2010 SP1 and SharePoint Foundation 2010 SP1 allows remote attackers to cause a denial of service (W3WP process crash and site outage) via a crafted URL, aka "Buffer Overflow Vulnerability."
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Analysis
by VulDB Data Team • 05/06/2021
The vulnerability identified as CVE-2013-0085 represents a critical buffer overflow flaw within Microsoft SharePoint Server 2010 SP1 and SharePoint Foundation 2010 SP1 implementations. This vulnerability resides in the web processing components of the SharePoint platform, specifically affecting the w3wp.exe process that handles web requests. The flaw manifests when the system processes specially crafted URLs that exceed the allocated buffer space, leading to memory corruption and subsequent process termination. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, where insufficient bounds checking allows attackers to write beyond allocated memory boundaries. This type of vulnerability falls within the ATT&CK framework's technique T1499.004 for Network Denial of Service, as it enables remote adversaries to disrupt service availability through controlled input manipulation.
The technical exploitation of this vulnerability requires an attacker to construct a malicious URL that triggers the buffer overflow condition in the SharePoint web processing pipeline. When the w3wp.exe worker process encounters such a malformed URL, it attempts to process the input without adequate boundary validation, causing the process to crash and restart. The crash results in immediate service disruption for all users accessing the affected SharePoint site, creating a denial of service condition that can persist until the system is manually restarted or the process recovers. The vulnerability affects the core web application framework and demonstrates how improper input validation can lead to complete service interruption rather than merely data corruption or privilege escalation. The buffer overflow occurs in the memory management layer where SharePoint processes HTTP requests, making it particularly dangerous as it can be triggered through standard web browsing activities without requiring authentication or special privileges.
The operational impact of CVE-2013-0085 extends beyond simple service interruption to encompass broader organizational disruption and potential financial consequences. When the w3wp.exe process crashes, all active SharePoint sessions are terminated, requiring users to re-authenticate and reload pages, which can severely impact productivity during business hours. The vulnerability affects organizations that rely heavily on SharePoint for collaboration, document management, and intranet services, as the disruption can cascade across multiple departments and applications built on the SharePoint platform. The crash frequency and duration can vary based on attack volume and system configuration, but typically results in site outages lasting from minutes to hours depending on the recovery mechanisms in place. Organizations with high availability requirements face particular risk as this vulnerability can be exploited repeatedly to maintain service disruption, potentially causing significant business impact and reputational damage.
Mitigation strategies for CVE-2013-0085 should prioritize immediate patch deployment from Microsoft as the primary defense mechanism, as the vulnerability was addressed through security updates specifically designed to correct the buffer overflow condition. Organizations should implement network-level protections such as web application firewalls that can detect and block malformed URLs before they reach the SharePoint servers. Input validation controls should be enhanced at multiple layers including perimeter defenses, application firewalls, and application-level checks to prevent malformed requests from reaching vulnerable components. System administrators should monitor w3wp.exe process stability and implement automated alerting for unexpected process termination events that could indicate exploitation attempts. Additional protective measures include implementing proper access controls to limit exposure, regularly updating SharePoint configurations to disable unnecessary features, and establishing incident response procedures that can quickly identify and contain exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies that protect against multiple attack vectors while ensuring business continuity through robust monitoring and recovery procedures.