CVE-2008-7257 in ASA 5580
Summary
by MITRE
CRLF injection vulnerability in +webvpn+/index.html in WebVPN on Cisco Adaptive Security Appliances (ASA) 5580 series devices with software before 8.1(2) allows remote attackers to inject arbitrary HTTP headers as demonstrated by a redirect attack involving a %0d%0aLocation%3a sequence in a URI, or conduct HTTP response splitting attacks via unspecified vectors, aka Bug ID CSCsr09163.
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Analysis
by VulDB Data Team • 12/30/2024
The CVE-2008-7257 vulnerability represents a critical CRLF injection flaw in Cisco Adaptive Security Appliances (ASA) 5580 series devices running software versions prior to 8.1(2). This vulnerability exists within the +webvpn+/index.html component of the WebVPN service, which serves as the primary interface for remote access and web-based management of Cisco ASA firewalls. The flaw enables remote attackers to manipulate HTTP headers through carefully crafted input sequences, fundamentally compromising the integrity of HTTP responses and potentially allowing for sophisticated attack vectors that could bypass security controls. The vulnerability specifically manifests when the system processes user-supplied input without proper sanitization, creating an opportunity for attackers to inject carriage return and line feed characters that can alter HTTP headers.
The technical exploitation of this vulnerability leverages the inherent characteristics of CRLF (Carriage Return Line Feed) sequences, which are standard delimiters in HTTP protocol communications. Attackers can inject sequences such as %0d%0aLocation%3a into URIs to manipulate the Location header in HTTP responses, enabling them to redirect users to malicious websites or perform HTTP response splitting attacks. This injection capability stems from insufficient input validation and sanitization within the WebVPN component's handling of user requests, particularly when processing URI parameters that are directly incorporated into HTTP response headers. The vulnerability's impact extends beyond simple redirection, as it can be used to inject arbitrary HTTP headers, potentially allowing attackers to manipulate cookies, cache control directives, or other critical response attributes that govern browser behavior and security policies.
The operational impact of CVE-2008-7257 is severe and multifaceted, affecting organizations that rely on Cisco ASA 5580 series devices for network security and remote access management. This vulnerability creates opportunities for man-in-the-middle attacks, session hijacking, and cache poisoning scenarios that could compromise the confidentiality and integrity of network communications. Attackers could redirect authenticated users to phishing sites, inject malicious content into web responses, or manipulate browser cache behavior to persistently deliver harmful payloads. The vulnerability particularly affects enterprises that depend on WebVPN functionality for remote employee access, as it undermines the trust model that security appliances are designed to maintain. Organizations using affected ASA versions face significant risk of unauthorized access to internal network resources and potential data exfiltration through manipulated HTTP responses that bypass normal security controls.
Organizations should implement immediate mitigations including upgrading to Cisco ASA software versions 8.1(2) or later, which contain the necessary patches to address the CRLF injection vulnerability. Network administrators should also consider implementing additional monitoring and logging of HTTP traffic patterns to detect potential exploitation attempts, particularly around URI parameters that may contain suspicious CRLF sequences. The vulnerability aligns with CWE-1107, which specifically addresses CRLF injection flaws in HTTP headers, and corresponds to ATT&CK technique T1190 for exploitation of web applications through HTTP header manipulation. Security teams should conduct comprehensive vulnerability assessments of their ASA deployments and review access controls to minimize potential attack surface, while also implementing web application firewalls or proxies that can filter out suspicious HTTP header sequences before they reach the vulnerable WebVPN component.