A vulnerability in the Cisco WebEx Recording Format (WRF) player used in Cisco WebEx Business Suite could allow an unauthenticated, remote attacker to crash the Cisco WebEx WRF player, and in some cases execute remote code with the privilege of the logged in user.
The vulnerability is due to a failure to properly validate input from the .wrf recording being played. An attacker could exploit this vulnerability by persuading a user to play a specially crafted .wrf recording in a vulnerable Cisco WebEx WRF player. This vulnerability cannot be triggered just by attending a WebEx meeting.
Cisco would like to thank the Microsoft Vulnerability Research (MSVR) team for reporting this vulnerability.
Cisco has confirmed the vulnerability in a security advisory and released software updates.
Indicators of Compromise
Cisco WebEx WRF players running on Microsoft Windows, Apple Mac OS X, and Linux platforms with the following client builds are vulnerable:
Cisco WebEx Business Suite client builds prior to T28.8 (28.8)
Cisco WebEx Business Suite client builds prior to T27LDSP32EP16 (27.32.16)
The vulnerability is due to improper processing of .wrf files by the affected software.
An unauthenticated, remote attacker could exploit this vulnerability by convincing a user to open a crafted .wrf file with the affected application. Processing the malicious file may trigger an exception handler corruption error that may allow the attacker to execute arbitrary code or cause the affected application to crash, resulting in a DoS condition.
The vulnerability cannot be triggered by users attending a WebEx session. To exploit the vulnerability, an attacker would need to convince a user to play a malicious .wrf file. The attacker may provide a file to the user and persuade the user to open or execute the file by using misleading language or instructions.
Cisco indicates through the CVSS score that proof-of-concept code exists; however, the code is not known to be publicly available.
Administrators are advised to apply the appropriate updates.
Users are advised not to open email messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in email messages are safe, they are advised not to open them.
Users are advised not to open media files from suspicious or unrecognized sources. If users cannot verify that media files are safe, they are advised not to open them.
Administrators are advised to monitor critical systems.
Cisco customers could receive automatic updates once a recording file that is hosted on a WebEx server is accessed. In addition, customers that installed the Cisco WebEx WRF Player manually could perform a manual install of a new version of the WebEx WRF Player at the following link: WebEx
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