CyberSecBulletin
CVE-2023-20045NVD status: Modified

A vulnerability in the web-based management interface of Cisco Small Business RV160 and RV260…

CVE-2023-20045 is a high-severity improper input validation vulnerability in Cisco Small Business RV Series Router Firmware from Cisco, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.99% chance of exploitation within 30 days, higher than 63% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Rv160 VPN Router Firmware to 1.0.01.04 or a later version.
  2. Update Rv160w Wireless-ac VPN Router Firmware to 1.0.01.04 or a later version.
  3. Update Rv260 VPN Router Firmware to 1.0.01.04 or a later version.
  4. Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
CiscoCisco Small Business RV Series Router FirmwareNot specified in the recordNot stated
CiscoRv160 VPN Router Firmwarebefore 1.0.01.041.0.01.04
CiscoRv160w Wireless-ac VPN Router Firmwarebefore 1.0.01.041.0.01.04
CiscoRv260 VPN Router Firmwarebefore 1.0.01.041.0.01.04
CiscoRv260p VPN Router With Poe Firmwarebefore 1.0.01.041.0.01.04

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
HighAdministrator-level access is required first.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

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

Scoring systemScoreSeverityScored by
CVSS 3.14.9MediumCNA (cisco.com)
CVSS 3.17.2HighNVD

Official description

A vulnerability in the web-based management interface of Cisco Small Business RV160 and RV260 Series VPN Routers could allow an authenticated, remote attacker to execute arbitrary commands on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by sending a crafted request to the web-based management interface of an affected device. A successful exploit could allow the attacker to execute arbitrary commands using root-level privileges on the affected device. To exploit this vulnerability, the attacker must have valid Administrator-level credentials on the affected device.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How developers prevent this class of flaw

  • Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

More Improper Input Validation vulnerabilities (CWE-20)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Cisco Small Business RV Series Router Firmware

All Cisco Small Business RV Series Router Firmware vulnerabilities

Recent Improper Input Validation vulnerabilities

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