CVE-2021-1503 in WebEx Network Recording Player
Summary
by MITRE • 06/04/2021
A vulnerability in Cisco Webex Network Recording Player for Windows and MacOS and Cisco Webex Player for Windows and MacOS could allow an attacker to execute arbitrary code on an affected system. This vulnerability is due to insufficient validation of values in Webex recording files that are in either Advanced Recording Format (ARF) or Webex Recording Format (WRF). An attacker could exploit this vulnerability by sending a user a malicious ARF or WRF file through a link or email attachment and persuading the user to open the file with the affected software on the local system. A successful exploit could allow the attacker to execute arbitrary code on the affected system with the privileges of the targeted user.
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Analysis
by VulDB Data Team • 06/07/2021
This vulnerability resides within Cisco Webex collaboration software products, specifically affecting the Network Recording Player and Webex Player applications available for both Windows and MacOS operating systems. The flaw represents a critical code execution vulnerability that stems from inadequate input validation mechanisms within the software's handling of multimedia recording files. The affected software processes Advanced Recording Format files and Webex Recording Format files without sufficient sanitization of user-supplied data, creating an exploitable condition that can be leveraged by remote attackers to gain unauthorized system access.
The technical implementation of this vulnerability involves the improper validation of file metadata and content structures within ARF and WRF format files. When a user opens a maliciously crafted recording file through the vulnerable Webex applications, the software fails to properly validate the integrity and structure of the file contents. This validation failure allows attacker-controlled data to be interpreted as executable instructions or to manipulate memory structures within the application's runtime environment. The vulnerability specifically manifests when the affected software attempts to parse and render the recording file content, providing an execution path for arbitrary code injection attacks that operate under the privileges of the logged-in user account.
The operational impact of this vulnerability extends beyond simple remote code execution, as it enables attackers to establish persistent access to compromised systems through the execution of malicious payloads. Successful exploitation allows threat actors to perform actions such as installing additional malware, modifying system configurations, accessing sensitive data, and potentially escalating privileges to system administrator levels depending on the target user's permissions. The attack vector relies on social engineering techniques to convince users to open malicious files, making this vulnerability particularly dangerous in enterprise environments where users may encounter such attachments in email communications or shared network locations. The vulnerability affects a wide range of Cisco Webex products and operating systems, increasing the potential attack surface for threat actors.
Organizations should implement immediate mitigations including restricting user access to potentially malicious file types through email filtering and endpoint protection solutions, disabling automatic playback of external recording files, and ensuring all affected Cisco Webex software is updated to patched versions. Network administrators should also consider implementing application whitelisting policies to prevent execution of untrusted recording files through the vulnerable applications. Security teams should monitor for suspicious email attachments and network traffic patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-129, which addresses insufficient validation of input data, and maps to ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain code execution. Regular patch management procedures should be enforced to prevent exploitation of this class of vulnerabilities, as the patched versions of Cisco Webex software address the input validation flaws that enable this attack vector.