CVE-2010-2730 in IIS
Summary
by MITRE
Buffer overflow in Microsoft Internet Information Services (IIS) 7.5, when FastCGI is enabled, allows remote attackers to execute arbitrary code via crafted headers in a request, aka "Request Header Buffer Overflow Vulnerability."
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Analysis
by VulDB Data Team • 03/04/2017
The CVE-2010-2730 vulnerability represents a critical buffer overflow flaw within Microsoft Internet Information Services version 7.5 that specifically manifests when FastCGI protocol handling is enabled. This vulnerability resides in the request header processing mechanism of IIS 7.5 and provides remote attackers with the capability to execute arbitrary code on the affected system. The flaw occurs due to inadequate input validation and bounds checking when processing HTTP request headers that are transmitted through the FastCGI interface, creating a pathway for malicious input to overwrite adjacent memory locations. The vulnerability is particularly dangerous because it can be exploited over the network without requiring authentication, making it accessible to any remote attacker who can send crafted HTTP requests to the vulnerable server.
The technical implementation of this buffer overflow stems from improper handling of request headers within the FastCGI module of IIS 7.5. When a FastCGI-enabled web server receives an HTTP request containing specially crafted headers, the application fails to properly validate the length of these headers before copying them into fixed-size buffers. This allows an attacker to send headers that exceed the allocated buffer space, causing a buffer overflow condition that can be leveraged to overwrite critical memory segments including return addresses and function pointers. The vulnerability is classified as a classic stack-based buffer overflow with potential for arbitrary code execution, and it aligns with CWE-121, which describes buffer overflow conditions where insufficient bounds checking allows data to overwrite adjacent memory locations. The flaw specifically affects the FastCGI request processing pipeline where IIS 7.5 handles requests forwarded to FastCGI applications, making it particularly relevant for web applications that utilize FastCGI for processing dynamic content.
The operational impact of CVE-2010-2730 extends beyond simple remote code execution to encompass complete system compromise and potential lateral movement within network environments. Successful exploitation allows attackers to gain arbitrary code execution with the privileges of the IIS worker process, typically running with high system privileges. This vulnerability can serve as a stepping stone for attackers to escalate privileges, pivot to other network systems, or establish persistent access through backdoor installation. The attack surface is significant since IIS 7.5 servers with FastCGI enabled are common in enterprise environments, particularly for hosting PHP applications and other dynamic content. The vulnerability also maps to several ATT&CK techniques including T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter), as attackers can leverage this flaw to execute malicious commands and scripts on compromised systems. Organizations running vulnerable IIS 7.5 configurations are at risk of data breaches, system compromise, and potential regulatory compliance violations, especially in environments where sensitive data is processed through web applications.
Mitigation strategies for CVE-2010-2730 should prioritize immediate patching of affected systems with Microsoft security updates, specifically the patches released in the Microsoft Security Bulletin MS10-070. Organizations should disable FastCGI functionality on IIS 7.5 servers where it is not required, as this removes the attack surface entirely. Network segmentation and firewall rules should be implemented to restrict access to vulnerable web servers, particularly limiting direct internet access to these systems. Security monitoring should be enhanced to detect anomalous HTTP request patterns that may indicate exploitation attempts, including unusually large request headers or malformed HTTP requests. Additionally, implementing application-level protections such as input validation, header length restrictions, and regular security assessments can help identify and prevent similar vulnerabilities. The vulnerability also underscores the importance of maintaining up-to-date security patches and following secure coding practices that emphasize proper input validation and memory management. Organizations should conduct regular vulnerability assessments and penetration testing to identify potential buffer overflow conditions in their web application infrastructure, particularly in environments where legacy applications may be running with outdated security controls.