Vulnerability Spotlight: Two vulnerabilities in Zoom could lead to code execution

A member of Cisco Talos discovered this vulnerability. Blog by Jon Munshaw.

Cisco Talos recently discovered two vulnerabilities in the popular Zoom video chatting application that could allow a malicious user to execute arbitrary code on victims’ machines. Video conferencing software has skyrocketed in popularity during the COVID-19 pandemic as individuals across the globe are encouraged to work from home and avoid close face-to-face contact with friends and family.

In accordance with our coordinated disclosure policy, Cisco Talos worked with Zoom to ensure that

these issues are resolved. TALOS-2020-1056 was fixed in May. Zoom fixed TALOS-2020-1055 server-side in a separate update, though Cisco Talos believes it still requires a fix on the client-side to completely resolve the security risk.

Vulnerability details

Zoom client application chat Giphy arbitrary file write (TALOS-2020-1055/CVE-2020-6109)

An exploitable path traversal vulnerability exists in the Zoom Client version 4.6.10 processes messages including animated GIFs. A specially crafted chat message can cause an arbitrary file write which could potentially be further abused to achieve arbitrary code execution. In order to trigger this vulnerability, an attacker needs to send a specially crafted message to a target user or a group.

Only Giphy servers were originally supposed to be used for this feature in Zoom. However, the content from an arbitrary server would be loaded in this case, which could be abused to further leak information or abuse other vulnerabilities.

Read the complete vulnerability advisoryhere for additional information.

Zoom client application chat code snippet remote code execution vulnerability (TALOS-2020-1056/CVE-2020-6110)

An exploitable partial path traversal vulnerability exists in the way Zoom Client version 4.6.10 processes messages including shared code snippets. A specially crafted chat message can cause an arbitrary binary planting which could be abused to achieve arbitrary code execution. An attacker needs to send a specially crafted message to a target user or a group to trigger this vulnerability. For the most severe effect, target user interaction is required.

Read the complete vulnerability advisoryhere for additional information.

Versions tested

Talos tested and confirmed that this vulnerability affects version 4.6.10 of the Zoom client application.

Coverage

The following SNORTⓇ rules will detect exploitation attempts. Note that additional rules may be released at a future date and current rules are subject to change pending additional vulnerability information. For the most current rule information, please refer to your Firepower Management Center or Snort.org.

Snort Rules: 45892 - 45895, 53686