CVE-2017-12257 in WebEx Meetings Server
Summary
by MITRE
A vulnerability in the web framework of Cisco WebEx Meetings Server could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the web interface of an affected system. The vulnerability is due to insufficient input validation of some parameters that are passed to the web server of the affected system. An attacker could exploit this vulnerability by convincing a user to follow a malicious link or by intercepting a user request and injecting malicious code into the request. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected web interface or allow the attacker to access sensitive browser-based information. Cisco Bug IDs: CSCve96608.
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Analysis
by VulDB Data Team • 01/15/2021
The vulnerability identified as CVE-2017-12257 represents a critical cross-site scripting flaw within Cisco WebEx Meetings Server's web framework, classified under CWE-79 which specifically addresses cross-site scripting vulnerabilities. This weakness exists due to inadequate input validation mechanisms that fail to properly sanitize user-supplied parameters before processing them within the web server environment. The vulnerability affects the web interface of the affected system and can be exploited remotely without authentication, making it particularly dangerous as it requires no prior access credentials or privileged positions to initiate an attack.
The technical exploitation of this vulnerability occurs through manipulation of parameters that are transmitted to the web server, where insufficient validation allows malicious payloads to be executed within the context of legitimate user sessions. Attackers can leverage this weakness by crafting malicious links that, when clicked by an unsuspecting user, would execute arbitrary script code in the victim's browser session. Alternatively, attackers can intercept user requests and inject malicious code directly into the request parameters, effectively hijacking the user's session. This dual exploitation vector increases the attack surface and makes the vulnerability more difficult to detect and prevent.
The operational impact of this vulnerability extends beyond simple script execution, as it can potentially enable attackers to access sensitive browser-based information and perform actions within the context of the affected web interface. This capability allows for session hijacking, data theft, and unauthorized access to user accounts that rely on the web interface for authentication. The vulnerability essentially compromises the integrity of the user's browser session and can lead to complete compromise of user accounts, especially when combined with other attack vectors or when users have elevated privileges within the system. The lack of authentication requirements means that any user visiting a malicious link or having their requests intercepted can become a victim.
Mitigation strategies for CVE-2017-12257 should prioritize immediate patching of affected Cisco WebEx Meetings Server installations with the vendor-provided security updates. Organizations should also implement robust input validation controls at multiple layers of their network infrastructure, including web application firewalls and proxy servers that can detect and block malicious payloads before they reach the vulnerable web interface. Network segmentation and monitoring solutions should be deployed to detect anomalous traffic patterns that may indicate exploitation attempts. Additionally, user education programs should emphasize the importance of verifying links and avoiding suspicious web content, while implementing Content Security Policy headers can provide an additional layer of protection against XSS attacks. This vulnerability aligns with ATT&CK technique T1059.007 which covers Scripting through web shell execution, and demonstrates the importance of proper input sanitization as outlined in OWASP Top 10 A03:2021 - Injection vulnerabilities.