CVE-2012-3937 in WebEx Recording Format Player
Summary
by MITRE
Buffer overflow in the Cisco WebEx Recording Format (WRF) player T27 before LD SP32 EP10 and T28 before T28.4 allows remote attackers to execute arbitrary code via a crafted WRF file, aka Bug ID CSCtz72967.
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Analysis
by VulDB Data Team • 04/18/2021
The vulnerability identified as CVE-2012-3937 represents a critical buffer overflow flaw within Cisco WebEx Recording Format player components, specifically affecting versions prior to LD SP32 EP10 for T27 and T28 before T28.4. This issue resides in the handling of WRF file structures, which are used to store and playback WebEx recordings that contain multimedia content including audio, video, and presentation materials. The flaw manifests when the affected player processes specially crafted WRF files that contain maliciously constructed data structures designed to exceed buffer boundaries.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the WRF player's parsing routines. When processing a maliciously constructed WRF file, the player fails to properly bounds-check data structures, particularly within the handling of audio and video stream headers. This allows attackers to overwrite adjacent memory locations with controlled data, potentially leading to arbitrary code execution. The buffer overflow occurs during the parsing of WRF file metadata and multimedia stream information, where the player allocates fixed-size buffers without sufficient validation of incoming data lengths.
From an operational perspective, this vulnerability presents a significant risk to organizations utilizing Cisco WebEx services, as it enables remote code execution without requiring authentication. Attackers can craft malicious WRF files and deliver them through various vectors including email attachments, web downloads, or malicious websites. Once a user opens the crafted file with the vulnerable player, the attacker gains the ability to execute arbitrary code on the victim's system with the privileges of the user running the player. This capability allows for complete system compromise, data exfiltration, and potential lateral movement within network environments.
The attack surface for this vulnerability extends beyond simple exploitation, as it aligns with several tactics from the MITRE ATT&CK framework including initial access through malicious file delivery and execution through legitimate system binaries. The vulnerability's classification as a buffer overflow maps directly to CWE-121, which describes heap-based buffer overflow conditions that can lead to arbitrary code execution. Organizations relying on WebEx for business communications face particular risk since these recordings are commonly shared across departments and with external partners, increasing the potential attack vectors.
Organizations should immediately implement mitigation strategies including patching affected systems to the latest Cisco software versions that address this vulnerability, as well as implementing network segmentation to limit access to WebEx services. Additional protective measures include deploying email filtering solutions that can detect and block malicious WRF files, implementing application whitelisting policies to restrict execution of untrusted WRF players, and conducting user awareness training about the risks of opening untrusted multimedia files. The vulnerability also underscores the importance of maintaining current software patches and following security best practices for multimedia file handling in enterprise environments.