CVE-2021-1502 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. The vulnerability is due to insufficient validation of values within Webex recording files formatted as either Advanced Recording Format (ARF) or Webex Recording Format (WRF). An attacker could exploit the 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. 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 exists within Cisco Webex collaboration software products that handle multimedia recording files using Advanced Recording Format or Webex Recording Format. The flaw represents a classic buffer overflow condition that occurs when the application fails to properly validate input data from these file formats. When processing maliciously crafted ARF or WRF files, the player application does not adequately sanitize the data structure, creating opportunities for attackers to manipulate memory layout and execute unauthorized code. The vulnerability stems from inadequate input validation mechanisms that should have been implemented to ensure file integrity before processing. This type of weakness aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which covers out-of-bounds writes in heap-based buffers. The attack vector requires social engineering to convince users to open malicious files, making it particularly dangerous in enterprise environments where users may not be security-aware.
The operational impact of this vulnerability extends beyond simple code execution to potential system compromise and data exfiltration. When successfully exploited, the malicious code runs with the privileges of the targeted user, potentially allowing attackers to establish persistent access, escalate privileges, or move laterally within networks. The vulnerability affects multiple operating systems including both Windows and MacOS platforms, indicating a widespread exposure across Cisco's user base. Attackers could leverage this weakness to deploy malware, steal credentials, or gain unauthorized access to sensitive corporate information. The fact that the attack requires user interaction through email attachments or web links means that organizations must consider both technical and human factors in their defensive strategies. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1203, which covers legitimate credentials and T1059, which covers command and scripting interpreter. The exploitability factor is relatively high due to the ease of delivery through common email and web channels.
Organizations should implement immediate mitigations including disabling automatic playback of potentially malicious files, implementing email filtering rules to block suspicious attachments, and updating to patched versions of Cisco Webex software. Network administrators should consider implementing endpoint detection and response solutions to monitor for suspicious file execution patterns. Security awareness training programs must emphasize the dangers of opening unexpected email attachments or clicking suspicious links, as these social engineering components are essential for successful exploitation. The vulnerability highlights the importance of secure coding practices and input validation in multimedia processing applications. Cisco has released patches addressing this issue, and organizations should prioritize deployment of these updates across all affected systems. Additional defensive measures include restricting user privileges, implementing application whitelisting policies, and conducting regular vulnerability assessments of collaboration software. The incident underscores the need for comprehensive security testing of file processing components and highlights the critical role of validating all external input sources in enterprise software applications.