CVE-2017-6669 in WebEx Network Recording Player
Summary
by MITRE
Multiple buffer overflow vulnerabilities exist in the Cisco WebEx Network Recording Player for Advanced Recording Format (ARF) files. An attacker could exploit these vulnerabilities by providing a user with a malicious ARF file via email or URL and convincing the user to launch the file. Exploitation of these vulnerabilities could cause an affected player to crash and, in some cases, could allow arbitrary code execution on the system of a targeted user. The Cisco WebEx Network Recording Player is an application that is used to play back WebEx meeting recordings that have been recorded on the computer of an online meeting attendee. The player can be automatically installed when the user accesses a recording file that is hosted on a WebEx server. The following client builds are affected by this vulnerability: Cisco WebEx Business Suite (WBS29) client builds prior to T29.13.130, Cisco WebEx Business Suite (WBS30) client builds prior to T30.17, Cisco WebEx Business Suite (WBS31) client builds prior to T31.10. Cisco Bug IDs: CSCvc47758 CSCvc51227 CSCvc51242.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/29/2020
The vulnerability described in CVE-2017-6669 represents a critical buffer overflow issue within Cisco WebEx Network Recording Player software, specifically affecting Advanced Recording Format files. This vulnerability resides in the client-side application that handles playback of WebEx meeting recordings, making it particularly dangerous as it can be triggered through simple user interaction with maliciously crafted files. The affected systems include various builds of Cisco WebEx Business Suite across multiple versions, with specific build numbers identified as vulnerable, creating a broad attack surface that spans different client implementations. The vulnerability's exploitation requires social engineering elements where attackers must convince victims to open malicious ARF files, typically delivered through email attachments or malicious URLs, making it particularly insidious in enterprise environments where users may not be adequately trained to recognize such threats.
The technical flaw manifests as multiple buffer overflow conditions within the ARF file parsing functionality of the WebEx Network Recording Player application. These buffer overflows occur when the player processes malformed ARF files, causing memory corruption that can lead to unpredictable behavior including application crashes or complete system compromise. The vulnerability's impact extends beyond simple denial of service as it potentially enables arbitrary code execution on targeted systems, representing a severe privilege escalation risk. The root cause of these buffer overflows can be traced to insufficient input validation and bounds checking within the ARF parser implementation, where the application fails to properly validate the size and structure of incoming file data before processing it. This type of vulnerability is classified as a CWE-121 heap-based buffer overflow in the context of the Common Weakness Enumeration framework, and aligns with ATT&CK technique T1203 for Exploitation for Client Execution, where adversaries leverage client-side vulnerabilities to execute malicious code.
The operational impact of this vulnerability is significant for organizations using Cisco WebEx services, as it creates a vector for remote code execution that could allow attackers to gain full control over affected systems. Successful exploitation could enable attackers to install malware, steal sensitive data, establish persistence mechanisms, or use compromised systems as launch points for further attacks within the network. The vulnerability affects the core functionality of WebEx recording playback, which is widely used in enterprise environments for collaboration and training purposes, making the potential impact widespread and severe. Organizations with legacy client builds that have not been updated are particularly vulnerable, as the affected builds span multiple major releases of the WebEx Business Suite, indicating a prolonged period of vulnerability exposure. The automatic installation capability of the WebEx player when accessing recordings from WebEx servers further amplifies the risk, as users may inadvertently trigger the exploit without recognizing the malicious nature of the content.
Organizations should immediately implement mitigation strategies including updating to the latest client builds that address these vulnerabilities, specifically targeting the build versions mentioned in the Cisco bug IDs CSCvc47758, CSCvc51227, and CSCvc51242. Network-based mitigations should include implementing web content filtering and email security solutions that can detect and block malicious ARF files before they reach end users. Security awareness training programs should be enhanced to educate users about the risks of opening unexpected attachments or clicking suspicious links, particularly those related to collaboration software. System administrators should consider implementing application whitelisting policies that restrict execution of unauthorized WebEx player versions and monitor for unusual network activity patterns that might indicate exploitation attempts. Additionally, organizations should conduct vulnerability assessments to identify all systems running affected client builds and ensure proper patch management processes are in place to prevent similar vulnerabilities from accumulating in the future. The vulnerability's classification under ATT&CK framework as a client-side exploitation technique emphasizes the need for comprehensive endpoint protection strategies that combine traditional antivirus solutions with behavioral monitoring and network segmentation to limit the potential blast radius of successful exploitation attempts.