CVE-2022-20699
About
Multiple vulnerabilities in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers could allow an attacker to do any of the following: Execute arbitrary code Elevate privileges Execute arbitrary commands Bypass authentication and authorization protections Fetch and run unsigned software Cause denial of service (DoS) For more information about these vulnerabilities, see the Details section of this advisory.
Rainforest analyst review
The critical flaw in this Cisco advisory is a stack-based buffer overflow in the SSL VPN module of the RV340, RV340W, RV345, and RV345P Small Business routers. When SSL VPN is enabled, the web server that terminates those tunnels fails to bounds-check attacker-supplied input in crafted HTTP requests, letting a remote, unauthenticated attacker smash the stack and run code as root on the device. There is no login step and no user interaction; reaching the gateway over the network is enough.
These are branch-office and small-business edge devices, which means the vulnerable service usually sits directly on the internet as the network's front door and its VPN concentrator. Compromising one hands an attacker a foothold inside the LAN behind it and control of the traffic passing through. Cisco did not release fixes for the older RV routers in this family, so for those the practical answer is to disable the SSL VPN feature if it is not required, block remote management, and plan replacement. Where patched firmware exists, apply it and treat any exposed unit as suspect.
References
- http://packetstormsecurity.com/files/167113/Cisco-RV340-SSL-VPN-Unauthenticated-Remote-Code-Execution.html
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smb-mult-vuln-KA9PK6D
- https://www.zerodayinitiative.com/advisories/ZDI-22-414/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-20699
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Frequently asked questions
What is CVE-2022-20699?
Multiple vulnerabilities in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers could allow an attacker to do any of the following: Execute arbitrary code Elevate privileges Execute arbitrary commands Bypass authentication and authorization protections Fetch and run unsigned software Cause denial of service (DoS) For more information about these vulnerabilities, see the Details section of this advisory…
How severe is CVE-2022-20699?
CVE-2022-20699 carries a CVSS 3.1 base score of 10, rated critical. On the Rainforest Risk Index — which weighs the severity alongside how easy the flaw is to reach and how broad its impact is — it scores 100 out of 100, in the critical band.
How is CVE-2022-20699 exploited?
According to the CVSS vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H): attack vector Network, attack complexity Low, privileges required None, user interaction None. Impact on confidentiality High, integrity High and availability High.
Which products are affected by CVE-2022-20699?
Public advisories list the following as affected: rv340, rv340 firmware, rv340w, rv340w firmware, rv345, rv345 firmware, +2. Check the references on this page for the exact versions each vendor confirms.
How do I fix CVE-2022-20699?
Apply the fix the vendor published — the references on this page link to the primary advisories and patches. When patching can't happen right away, reduce the exposure of the affected component and watch it for exploitation attempts. Rainforest customers see this vulnerability correlated to their own assets and prioritized by real exposure, not by score alone.
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