CVE-2022-20810: Cisco IOS XE Information Disclosure Flaw

CVE-2022-20810 Overview

A vulnerability in the Simple Network Management Protocol (SNMP) of Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family could allow an authenticated, remote attacker to access sensitive information. This vulnerability is due to insufficient restrictions that allow a sensitive configuration detail to be disclosed. An attacker could exploit this vulnerability by retrieving data through SNMP read-only community access. A successful exploit could allow the attacker to view Service Set Identifier (SSID) preshared keys (PSKs) that are configured on the affected device.

Critical Impact

Authenticated attackers can retrieve SSID preshared keys (PSKs) via SNMP, potentially compromising wireless network security across the entire enterprise.

Affected Products

• Cisco IOS XE
• Cisco Catalyst 9800 Wireless Controller
• Cisco Catalyst 9800-40 Wireless Controller
• Cisco Catalyst 9800-80 Wireless Controller
• Cisco Catalyst 9800-CL Cloud Wireless Controller
• Cisco Catalyst 9800-L Wireless Controller
• Cisco Catalyst 9800-L-C Wireless Controller
• Cisco Catalyst 9800-L-F Wireless Controller
• Cisco Catalyst 9800 Embedded Wireless Controller

Discovery Timeline

• September 30, 2022 - CVE-2022-20810 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-20810

Vulnerability Analysis

This Information Disclosure vulnerability affects the SNMP implementation in Cisco IOS XE Wireless Controller Software. The core issue lies in insufficient access controls within the SNMP subsystem, which fails to properly restrict access to sensitive wireless configuration data. When an attacker with valid SNMP read-only credentials queries specific SNMP OIDs (Object Identifiers), the system improperly returns SSID preshared keys that should be protected.

The vulnerability is classified under CWE-202 (Exposure of Sensitive Information Through Data Queries), indicating that the SNMP implementation exposes sensitive data that should not be accessible even to authenticated users with read-only permissions. PSKs are critical security credentials that should never be exposed through management protocols, regardless of authentication level.

Root Cause

The root cause of this vulnerability is improper information exposure through the SNMP data query mechanism. The Cisco IOS XE Wireless Controller Software fails to implement adequate restrictions on which configuration elements are accessible via SNMP read operations. Specifically, the software does not properly mask or exclude SSID preshared keys from SNMP queries, allowing any user with read-only SNMP community string access to retrieve these sensitive credentials.

Attack Vector

The attack vector for CVE-2022-20810 is network-based and requires low-privilege authentication. An attacker must have knowledge of the SNMP read-only community string to exploit this vulnerability. The attack flow typically involves:

1. The attacker gains access to the SNMP read-only community string through configuration exposure, social engineering, or default credential usage
2. Using SNMP management tools, the attacker queries the affected Cisco wireless controller for configuration data
3. The vulnerable SNMP implementation returns SSID preshared keys without proper redaction
4. The attacker can then use the obtained PSKs to gain unauthorized access to wireless networks or conduct further attacks

The vulnerability requires network access to the SNMP service on the affected device, which is typically accessible on UDP port 161. No user interaction is required for exploitation.

Detection Methods for CVE-2022-20810

Indicators of Compromise

• Unusual SNMP query patterns targeting wireless configuration OIDs from unexpected source addresses
• High volume of SNMP GET/GETNEXT requests to the wireless controller management interface
• SNMP queries originating from non-administrative workstations or external networks
• Authentication logs showing SNMP access from unknown or unauthorized hosts

Detection Strategies

• Monitor SNMP traffic to Catalyst 9800 series controllers for queries requesting wireless configuration data
• Implement SNMP access logging and review logs for unusual query patterns or sources
• Deploy network intrusion detection rules to identify bulk SNMP enumeration attempts
• Configure alerts for SNMP access attempts from non-whitelisted IP addresses

Monitoring Recommendations

• Enable SNMP logging on all affected Cisco wireless controllers to track query sources and types
• Implement network segmentation to restrict SNMP access to dedicated management networks
• Use SentinelOne Singularity platform to monitor for post-exploitation activity such as unauthorized wireless network connections
• Regularly audit SNMP community strings and access control lists on network infrastructure

How to Mitigate CVE-2022-20810

Immediate Actions Required

• Apply the latest security patches from Cisco as detailed in the Cisco Security Advisory
• Review and strengthen SNMP community strings, replacing any default or weak credentials
• Restrict SNMP access to trusted management hosts only using access control lists
• Consider disabling SNMP if not required for network management operations
• Rotate all SSID preshared keys that may have been exposed on affected devices

Patch Information

Cisco has released software updates to address this vulnerability. Administrators should consult the Cisco Security Advisory for specific version information and upgrade paths. The advisory provides detailed guidance on which software releases contain the fix and the recommended upgrade procedures for each affected product in the Catalyst 9800 family.

Workarounds

• Implement SNMP access control lists (ACLs) to restrict queries to authorized management stations only
• Use SNMPv3 with authentication and encryption to provide stronger access controls
• Disable SNMP if not operationally required until patches can be applied
• Segment management networks to prevent unauthorized access to SNMP services from untrusted network zones

# Example: Configure SNMP access restriction on Cisco IOS XE
# Restrict SNMP access to specific management hosts only
access-list 99 permit 10.0.10.5
access-list 99 permit 10.0.10.6
access-list 99 deny any log

# Apply ACL to SNMP community
snmp-server community [COMMUNITY-STRING] RO 99

# Enable SNMPv3 with authentication and encryption
snmp-server group MGMT-GROUP v3 priv
snmp-server user ADMIN MGMT-GROUP v3 auth sha [AUTH-PASSWORD] priv aes 256 [PRIV-PASSWORD]