CVE-2020-3347: Cisco Webex Information Disclosure Flaw

CVE-2020-3347 Overview

A vulnerability in Cisco Webex Meetings Desktop App for Windows could allow an authenticated, local attacker to gain access to sensitive information on an affected system. The vulnerability is due to unsafe usage of shared memory that is used by the affected software. An attacker with permissions to view system memory could exploit this vulnerability by running an application on the local system that is designed to read shared memory. A successful exploit could allow the attacker to retrieve sensitive information from the shared memory, including usernames, meeting information, or authentication tokens that could aid the attacker in future attacks.

Critical Impact

Local attackers can extract sensitive information including usernames, meeting details, and authentication tokens from shared memory, potentially enabling further attacks against the organization.

Affected Products

• Cisco Webex Meetings Desktop App for Windows (all versions prior to patch)
• Cisco Webex Meetings Desktop App version 40.6.0 for Windows

Discovery Timeline

• 2020-06-18 - CVE-2020-3347 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-3347

Vulnerability Analysis

This vulnerability falls under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) and affects the Cisco Webex Meetings Desktop App for Windows. The flaw stems from improper handling of shared memory regions used by the application for inter-process communication or data storage.

The vulnerability requires local access to the affected system. An attacker must have valid credentials and permissions to view system memory to exploit this flaw. The impact is confined to confidentiality, as the attacker can only read sensitive data but cannot modify system state or cause service disruption.

The attack requires low complexity to execute, as the attacker simply needs to develop or utilize a tool capable of reading shared memory segments used by the Webex application. No user interaction is required once the attacker has local access.

Root Cause

The root cause of CVE-2020-3347 lies in the unsafe usage of shared memory by the Cisco Webex Meetings Desktop App. The application stores sensitive information—including usernames, meeting information, and authentication tokens—in shared memory regions without adequate access controls or encryption.

Shared memory is a common inter-process communication mechanism in Windows, but when sensitive data is stored in these regions without proper protection, any process running on the same system with sufficient privileges can access this data. The Webex application failed to implement appropriate security measures such as restricting memory access permissions or encrypting sensitive data before storing it in shared memory.

Attack Vector

The attack vector for CVE-2020-3347 is local, requiring the attacker to have authenticated access to the target Windows system. The exploitation process involves:

1. The attacker gains local access to a system where Cisco Webex Meetings Desktop App is installed and in use
2. The attacker runs a custom application or memory inspection tool designed to enumerate and read shared memory regions
3. The attacker identifies the shared memory segments used by the Webex application
4. The attacker extracts sensitive information such as usernames, active meeting details, and authentication tokens
5. The extracted tokens and credentials can then be leveraged for lateral movement, session hijacking, or further targeted attacks

The attack does not require the attacker to interact with the Webex application directly—simply having the ability to read shared memory on the local system is sufficient.

Detection Methods for CVE-2020-3347

Indicators of Compromise

• Unusual processes accessing shared memory regions associated with Webex Meetings
• Unauthorized local applications with memory inspection capabilities running on endpoints
• Evidence of memory dumping tools or custom executables in user directories
• Abnormal access patterns to Webex-related processes by non-Webex applications

Detection Strategies

• Monitor for process creation events involving known memory inspection or dumping utilities
• Implement application whitelisting to prevent unauthorized memory access tools from executing
• Enable detailed Windows Security Event logging, particularly for process access events (Event ID 4663)
• Deploy endpoint detection and response (EDR) solutions to detect suspicious memory access patterns

Monitoring Recommendations

• Configure alerts for any process attempting to access Webex Meetings Desktop App memory space
• Monitor for reconnaissance activities on shared memory objects using tools like Windows Sysinternals
• Review authentication logs for unusual login patterns that may indicate token theft
• Establish baselines for normal Webex process behavior and alert on deviations

How to Mitigate CVE-2020-3347

Immediate Actions Required

• Update Cisco Webex Meetings Desktop App to the latest patched version immediately
• Review and audit local user permissions to minimize accounts with elevated privileges
• Implement application control policies to restrict execution of unauthorized memory access tools
• Monitor affected systems for signs of exploitation while patches are being deployed

Patch Information

Cisco has released a security patch addressing CVE-2020-3347. Administrators should consult the Cisco Security Advisory for detailed patch information and upgrade instructions. The advisory provides specific version information for remediated releases of the Webex Meetings Desktop App for Windows.

Organizations should prioritize updating all instances of the Cisco Webex Meetings Desktop App across their enterprise to ensure protection against this information disclosure vulnerability.

Workarounds

• Restrict local access to systems running Webex Meetings to only trusted users
• Implement strict application control policies to prevent unauthorized programs from running
• Consider deploying network-level monitoring to detect any exfiltration of stolen credentials
• Review and limit shared memory permissions where possible at the operating system level
• Enable multi-factor authentication for Webex accounts to mitigate impact of token theft

# Example: Monitor for suspicious Webex memory access on Windows using Sysmon
# Add this rule to your Sysmon configuration to detect process access to Webex
# <ProcessAccess onmatch="include">
#   <TargetImage condition="contains">webex</TargetImage>
#   <SourceImage condition="excludes">webex</SourceImage>
# </ProcessAccess>