CVE-2001-0524 in SecureIIS
Summary
by MITRE
eEye SecureIIS versions 1.0.3 and earlier does not perform length checking on individual HTTP headers, which allows a remote attacker to send arbitrary length strings to IIS, contrary to an advertised feature of SecureIIS versions 1.0.3 and earlier.
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Analysis
by VulDB Data Team • 04/08/2019
The vulnerability described in CVE-2001-0524 represents a critical security flaw in eEye SecureIIS versions 1.0.3 and earlier, where the software fails to properly validate the length of individual HTTP headers. This weakness directly contradicts the security assertions made by the product, which was designed to provide enhanced protection for Microsoft Internet Information Server environments. The issue stems from the application's failure to implement proper input validation mechanisms that would normally prevent maliciously crafted HTTP requests from being processed. SecureIIS was marketed as a solution to harden IIS against various attacks, yet this vulnerability demonstrates a fundamental flaw in its implementation that undermines its core security promise.
This technical flaw constitutes a classic buffer overflow vulnerability, specifically categorized under CWE-122 which deals with insufficient length checks for buffers. The vulnerability allows remote attackers to exploit the lack of header length validation by sending HTTP requests containing unusually long header values that exceed normal expectations. When IIS processes these malformed headers, the application's inability to properly handle extended input data creates opportunities for exploitation that could lead to denial of service conditions or potentially more severe consequences depending on how the system handles the malformed data. The flaw operates at the protocol level where HTTP headers are parsed and processed, making it particularly dangerous as it can be triggered through standard web browsing activities.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it fundamentally compromises the integrity of the security model that SecureIIS was intended to provide. Attackers can leverage this weakness to disrupt web server operations, potentially causing system instability or crashes that affect legitimate users. From an attacker's perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the T1499 category for network denial of service, where adversaries exploit weaknesses in network protocols to disrupt services. The vulnerability also falls under T1071 which covers application layer protocols, as it specifically targets HTTP header processing. Organizations using affected versions of SecureIIS face significant risk of service disruption and potential compromise of their web infrastructure.
Mitigation strategies for this vulnerability require immediate action to address the root cause through proper input validation implementation. System administrators should upgrade to newer versions of SecureIIS that properly implement header length checking mechanisms, or alternatively deploy network-level protections such as intrusion detection systems that can identify and block malformed HTTP traffic patterns. The fix should include comprehensive validation of all HTTP header values to ensure they conform to expected length parameters and reject any requests that exceed predetermined limits. Additionally, implementing proper logging and monitoring of HTTP header processing can help detect exploitation attempts and provide forensic evidence for security investigations. Organizations should also consider implementing network segmentation and access controls to limit exposure to this vulnerability while remediation efforts are underway, ensuring that the security posture of their web infrastructure is maintained during the patching process.