CVE-2009-4910 in ASA 5580
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the WebVPN portal on Cisco Adaptive Security Appliances (ASA) 5580 series devices with software before 8.1(2) allows remote attackers to inject arbitrary web script or HTML via unspecified vectors, aka Bug ID CSCsq78418.
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Analysis
by VulDB Data Team • 04/20/2017
The CVE-2009-4910 vulnerability represents a critical cross-site scripting flaw discovered in Cisco Adaptive Security Appliances (ASA) 5580 series devices running software versions prior to 8.1(2). This vulnerability specifically affects the WebVPN portal component of these network security appliances, creating a significant attack surface that remote threat actors can exploit to execute malicious code within the context of authenticated user sessions. The vulnerability was identified through Cisco's internal bug tracking system under the reference CSCsq78418, highlighting the importance of proper input validation and output encoding mechanisms in web-based administrative interfaces. The flaw resides in how the WebVPN portal processes user-supplied input data, failing to properly sanitize or escape special characters that could be interpreted as executable script code by web browsers.
The technical nature of this vulnerability stems from insufficient validation of user input within the WebVPN portal's processing pipeline. Attackers can leverage this weakness by crafting malicious payloads that contain script tags or other HTML elements designed to execute in the browser context of legitimate users who access the compromised portal. The unspecified vectors suggest that multiple input points within the WebVPN interface could serve as potential attack entry points, including form fields, URL parameters, or other user-controllable data elements. This XSS vulnerability operates at the application layer and can be exploited without requiring authentication to the underlying ASA device itself, making it particularly dangerous as it can be triggered by any user who accesses the vulnerable portal. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and represents a classic example of how web application security controls can be bypassed through inadequate input sanitization.
The operational impact of CVE-2009-4910 extends beyond simple script execution, as it can enable attackers to perform session hijacking, steal user credentials, redirect victims to malicious sites, or even modify web content displayed to authenticated users. In the context of network security appliances like the ASA 5580 series, this vulnerability compromises the integrity of the administrative interface and potentially exposes sensitive network configurations to unauthorized access. The attack can be particularly devastating in enterprise environments where the WebVPN portal serves as a gateway for remote access to internal network resources, allowing attackers to gain persistent access to corporate networks through compromised user sessions. This vulnerability directly impacts the CIA triad by potentially compromising confidentiality through credential theft, integrity through content manipulation, and availability through potential service disruption. The exploitation of this flaw can lead to complete compromise of the network security posture, as attackers can use the WebVPN portal as a foothold for further lateral movement within the network infrastructure.
Mitigation strategies for CVE-2009-4910 primarily focus on implementing the most effective immediate solution which is upgrading the affected Cisco ASA 5580 series devices to software version 8.1(2) or later. This update addresses the core input validation issues that enable the XSS attack vectors and provides proper encoding mechanisms for user-supplied data. Network administrators should also implement additional defensive measures including web application firewalls that can detect and block suspicious script injection attempts, proper input validation at multiple layers of the application stack, and regular security assessments of web-based administrative interfaces. The implementation of Content Security Policy headers can provide additional protection against script execution, while regular monitoring of web portal access logs can help detect anomalous user behavior indicative of exploitation attempts. Organizations should also consider implementing network segmentation to limit the potential impact of successful exploitation, and establish incident response procedures specifically designed to address web application vulnerabilities in security appliances. This vulnerability serves as a reminder of the critical importance of maintaining current security software versions and implementing comprehensive web application security controls to protect against persistent threats targeting network infrastructure components.