CVE-2005-4734 in Authentication Agent for Web
Summary
by MITRE
Stack-based buffer overflow in IISWebAgentIF.dll in RSA Authentication Agent for Web (aka SecurID Web Agent) 5.2 and 5.3 for IIS allows remote attackers to execute arbitrary code via a long url parameter in the Redirect method.
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Analysis
by VulDB Data Team • 07/05/2019
The vulnerability described in CVE-2005-4734 represents a critical stack-based buffer overflow in the IISWebAgentIF.dll component of RSA Authentication Agent for Web versions 5.2 and 5.3. This flaw exists within the SecurID Web Agent implementation that integrates with Microsoft Internet Information Services, creating a dangerous attack surface that enables remote code execution. The vulnerability specifically manifests when processing the Redirect method with excessively long URL parameters, allowing malicious actors to manipulate memory layout and potentially gain full system control. The affected software component operates as a web agent that facilitates authentication processes for RSA SecurID tokens, making it a prime target for attackers seeking to compromise authentication infrastructure.
The technical mechanism behind this vulnerability involves a classic stack buffer overflow condition where the IISWebAgentIF.dll fails to properly validate input length when handling URL parameters in the Redirect method. When an attacker crafts a malicious request containing an overly long parameter value, the software attempts to copy this data into a fixed-size buffer on the stack without adequate bounds checking. This insufficient validation creates a situation where the input data exceeds the allocated buffer space, causing adjacent memory locations to be overwritten. The overflow can corrupt return addresses, function pointers, and other critical stack data, providing attackers with the opportunity to redirect program execution flow. According to CWE-121, this vulnerability maps directly to stack-based buffer overflow conditions that occur when insufficient bounds checking allows data to overwrite adjacent stack memory regions.
The operational impact of this vulnerability extends beyond simple remote code execution, as it fundamentally compromises the security posture of systems running vulnerable RSA Authentication Agents. Attackers can leverage this weakness to bypass authentication mechanisms, escalate privileges, and potentially establish persistent access to the web server infrastructure. The vulnerability affects organizations that rely on RSA SecurID authentication for their web applications, particularly those with IIS-based deployments where the agent is installed. Given that the attack can be executed remotely without authentication, the exploitability is high and the potential damage significant. The vulnerability affects both versions 5.2 and 5.3, indicating it was likely introduced in a specific code change and persisted through the release cycle, highlighting the importance of proper input validation in security-critical components.
Mitigation strategies for this vulnerability should include immediate patching of affected systems with the vendor-provided security updates from RSA. Organizations must also implement network-level protections such as web application firewalls and input validation rules that can detect and block malformed URL parameters before they reach the vulnerable component. The implementation of proper input sanitization and bounds checking in the application code represents a fundamental defensive measure that aligns with the principles outlined in the ATT&CK framework for defensive techniques related to input validation and buffer overflow prevention. Additionally, network segmentation and access controls should be enforced to limit the potential impact of successful exploitation, while security monitoring should be enhanced to detect anomalous traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of validating all external inputs and implementing robust error handling in security-critical software components that interface with web servers.