CVE-2022-20705 – This critical vulnerability in Cisco Small Busi... (How to Fix)

Q: What is the severity of CVE-2022-20705?

CVE-2022-20705 has a CVSS score of 10.0 (CRITICAL). This critical vulnerability in Cisco Small Business RV Series routers allows attackers to bypass authentication, execute arbitrary commands with root privileges, and take complete control of affected devices. It affects RV160, RV260, RV340, and RV345 series routers running vulnerable firmware versions. Attackers can exploit this remotely without authentication to compromise the entire network.

📋 TL;DR

This critical vulnerability in Cisco Small Business RV Series routers allows attackers to bypass authentication, execute arbitrary commands with root privileges, and take complete control of affected devices. It affects RV160, RV260, RV340, and RV345 series routers running vulnerable firmware versions. Attackers can exploit this remotely without authentication to compromise the entire network.

💻 Affected Systems

Products:

Cisco RV160
Cisco RV260
Cisco RV340
Cisco RV345

Versions: All versions prior to 1.0.03.24

Operating Systems: Cisco IOS-based firmware

Default Config Vulnerable: ⚠️ Yes

Notes: All default configurations are vulnerable. No special configuration required for exploitation.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete network compromise: attacker gains root access, installs persistent malware, intercepts all network traffic, pivots to internal systems, and causes permanent damage to router hardware.

🟠

Likely Case

Router takeover leading to credential theft, network monitoring, installation of backdoors, and potential ransomware deployment across connected systems.

🟢

If Mitigated

Limited impact if routers are behind firewalls, have restricted management interfaces, and proper network segmentation prevents lateral movement.

🌐 Internet-Facing: HIGH - Routers are typically internet-facing devices with management interfaces exposed, making them prime targets for remote exploitation.

🏢 Internal Only: MEDIUM - Internal attackers could exploit if they gain network access, but external exposure is the primary concern.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: CONFIRMED

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Multiple public exploits available including authentication bypass and command injection. Exploitation requires only HTTP access to the router's web interface.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 1.0.03.24 and later

Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smb-mult-vuln-KA9PK6D

Restart Required: Yes

Instructions:

1. Download firmware 1.0.03.24 or later from Cisco's website. 2. Log into router web interface. 3. Navigate to Administration > Firmware Upgrade. 4. Upload the new firmware file. 5. Wait for automatic reboot (approximately 5-10 minutes).

🔧 Temporary Workarounds

Disable Web Management Interface

all

Disable the vulnerable web interface to prevent exploitation while awaiting patch

configure terminal
no ip http server
no ip http secure-server
end
write memory

Restrict Management Access

all

Limit management interface access to specific trusted IP addresses only

configure terminal
ip http access-class MANAGEMENT-ACL
ip http secure-server access-class MANAGEMENT-ACL
end
write memory

🧯 If You Can't Patch

Immediately isolate affected routers from internet by moving behind a firewall
Implement strict network segmentation to limit potential lateral movement from compromised routers

🔍 How to Verify

Check if Vulnerable:

Check firmware version via web interface: System Summary > Firmware Version. If version is below 1.0.03.24, device is vulnerable.

Check Version:

show version (via CLI) or check web interface System Summary page

Verify Fix Applied:

After patching, verify firmware version shows 1.0.03.24 or higher in System Summary > Firmware Version.

📡 Detection & Monitoring

Log Indicators:

Multiple failed login attempts followed by successful login from unusual IP
Web interface access from unexpected sources
Configuration changes without authorized user activity

Network Indicators:

Unusual outbound connections from router to unknown IPs
Sudden increase in traffic from router management interface
DNS queries to suspicious domains from router

SIEM Query:

source="cisco-router" AND (event_type="authentication" AND result="success" AND src_ip NOT IN [trusted_ips]) OR (event_type="configuration_change" AND user="unknown")

📊 Metadata

CVE ID: CVE-2022-20705

CVSS v3 Score: 10.0 (CRITICAL)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CWE: CWE-121

Published: February 10, 2022

Last Updated: November 21, 2024

🔗 References

http://packetstormsecurity.com/files/170988/Cisco-RV-Series-Authentication-Bypass-Command-Injection.html
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smb-mult-vuln-KA9PK6D Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-22-409/ Third Party Advisory,VDB Entry
https://www.zerodayinitiative.com/advisories/ZDI-22-410/ Third Party Advisory,VDB Entry
https://www.zerodayinitiative.com/advisories/ZDI-22-415/ Third Party Advisory,VDB Entry
http://packetstormsecurity.com/files/170988/Cisco-RV-Series-Authentication-Bypass-Command-Injection.html
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smb-mult-vuln-KA9PK6D Vendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-22-409/ Third Party Advisory,VDB Entry
https://www.zerodayinitiative.com/advisories/ZDI-22-410/ Third Party Advisory,VDB Entry
https://www.zerodayinitiative.com/advisories/ZDI-22-415/ Third Party Advisory,VDB Entry

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