CVE-2024-20504 in Secure Email
Summary
by MITRE • 11/06/2024
A vulnerability in the web-based management interface of Cisco AsyncOS Software for Cisco Secure Email and Web Manager, Secure Email Gateway, and Secure Web Appliance could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the interface.
This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user of an affected interface to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.
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Analysis
by VulDB Data Team • 08/08/2025
The vulnerability identified as CVE-2024-20504 represents a critical security flaw in Cisco's AsyncOS software ecosystem, specifically affecting the web-based management interfaces of several security appliances including the Cisco Secure Email and Web Manager, Secure Email Gateway, and Secure Web Appliance. This vulnerability resides within the authentication and input validation mechanisms of the web interface, creating a pathway for malicious actors to compromise the security posture of organizations relying on these platforms. The flaw stems from inadequate sanitization of user-supplied data, which allows malicious input to persist within the system and subsequently execute when accessed by legitimate users. This type of vulnerability is particularly dangerous because it leverages the trust relationship between the web interface and its users, making it difficult to detect and prevent.
The technical exploitation of this vulnerability follows a classic stored cross-site scripting attack pattern where an attacker crafts malicious input and stores it within the affected system's database or interface elements. When an authenticated user navigates to a page containing the malicious input or clicks on a specially crafted link, the stored script executes within the user's browser context. This allows the attacker to perform actions as if they were the legitimate user, potentially gaining access to sensitive information, modifying system configurations, or redirecting users to malicious websites. The vulnerability specifically affects the web-based management interface, meaning that any user with valid credentials could be targeted, regardless of their privilege level within the system. This characteristic aligns with CWE-79 which categorizes cross-site scripting vulnerabilities as a fundamental web application security issue.
The operational impact of CVE-2024-20504 extends beyond simple script execution, as it can enable more sophisticated attacks including session hijacking, credential theft, and privilege escalation within the affected system. Attackers could potentially use this vulnerability to establish persistent access to the management interface, monitor administrator activities, or manipulate security policies. The fact that this vulnerability requires only authentication to exploit means that it could be leveraged by insiders or compromised users, making it particularly concerning for organizations with robust perimeter security but weaker internal authentication controls. This vulnerability also creates opportunities for attackers to gather sensitive information about the network infrastructure, system configurations, and potentially other connected systems through browser-based data exfiltration techniques.
Organizations should immediately implement mitigation strategies focusing on input validation and output encoding within the affected web interfaces. The most effective immediate response involves updating to the latest software versions that contain patches addressing this specific vulnerability. Network segmentation and privileged access controls should be reviewed to minimize the potential impact of successful exploitation, while monitoring systems should be enhanced to detect unusual activity patterns that might indicate XSS attack attempts. The vulnerability also highlights the importance of regular security assessments of web-based management interfaces and the implementation of web application firewalls to detect and prevent malicious input. From an ATT&CK framework perspective, this vulnerability maps to techniques involving client-side attacks and credential access, emphasizing the need for comprehensive endpoint protection and user education programs to reduce the success rate of such attacks. Additionally, organizations should consider implementing automated scanning tools to identify similar input validation flaws in other web applications within their environment, as the underlying issue of insufficient input validation represents a common security weakness across many platforms.