CVE-2021-1322 – This vulnerability allows authenticated attacke... (How to Fix)

Q: What is the severity of CVE-2021-1322?

CVE-2021-1322 has a CVSS score of 7.2 (HIGH). This vulnerability allows authenticated attackers with administrator credentials to execute arbitrary code as root or cause denial of service on affected Cisco Small Business routers. The issue stems from improper input validation in the web management interface. Organizations using these specific router models are affected.

📋 TL;DR

This vulnerability allows authenticated attackers with administrator credentials to execute arbitrary code as root or cause denial of service on affected Cisco Small Business routers. The issue stems from improper input validation in the web management interface. Organizations using these specific router models are affected.

💻 Affected Systems

Products:

Cisco Small Business RV016
RV042
RV042G
RV082
RV320
RV325 Routers

Versions: All versions prior to the fixed releases

Operating Systems: Embedded router OS

Default Config Vulnerable: ⚠️ Yes

Notes: All default configurations are vulnerable. The web management interface is typically enabled by default.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete device compromise allowing root-level arbitrary code execution, potentially leading to network infiltration, data theft, or persistent backdoor installation.

🟠

Likely Case

Device reboot causing temporary denial of service, disrupting network connectivity for connected users and services.

🟢

If Mitigated

Limited impact if strong access controls prevent unauthorized administrative access to the web interface.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: LOW

Exploitation requires valid administrator credentials but involves simple HTTP request crafting once authenticated.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: RV016: 4.2.3.14, RV042/RV042G: 4.2.3.14, RV082: 4.2.3.14, RV320/RV325: 1.5.1.11

Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-rv-overflow-ghZP68yj

Restart Required: Yes

Instructions:

1. Log into router web interface. 2. Navigate to Administration > Firmware Upgrade. 3. Download appropriate firmware from Cisco website. 4. Upload and install firmware. 5. Router will reboot automatically.

🔧 Temporary Workarounds

Restrict Web Interface Access

all

Limit access to the web-based management interface to trusted IP addresses only

Disable Remote Management

all

Turn off remote management if not required, limiting interface access to local network only

🧯 If You Can't Patch

Implement strict network segmentation to isolate affected routers from critical systems
Enforce strong, unique administrator credentials and enable multi-factor authentication if supported

🔍 How to Verify

Check if Vulnerable:

Check router firmware version via web interface: Status > Router > Firmware Version

Check Version:

No CLI command - use web interface at Status > Router > Firmware Version

Verify Fix Applied:

Confirm firmware version matches or exceeds patched versions listed in vendor advisory

📡 Detection & Monitoring

Log Indicators:

Multiple failed authentication attempts followed by successful login and unusual HTTP requests
Unexpected device reboots in system logs

Network Indicators:

Unusual HTTP POST requests to web management interface endpoints
Traffic patterns suggesting reconnaissance of router management interface

SIEM Query:

source="router_logs" AND (event="authentication_success" OR event="http_request") AND (uri CONTAINS "/admin/" OR uri CONTAINS "/cgi-bin/")

📊 Metadata

CVE ID: CVE-2021-1322

CVSS v3 Score: 7.2 (HIGH)

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

CWE: CWE-121

Published: February 4, 2021

Last Updated: November 21, 2024

🔗 References

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🔗 Related Vulnerabilities

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