Cisco Small Business RV Series Router Firmware: Improper Neutralization of Special Elements used in an OS Command
CVE-2022-20827 is a critical-severity improper neutralization of special elements used in an OS command vulnerability in Cisco Small Business RV Series Router Firmware from Cisco, with a CVSS 3.1 base score of 10.0 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 1.98% chance of exploitation within 30 days, higher than 81% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Rv160 Firmware to 1.0.01.05 or a later version.
- Update Rv160w Firmware to 1.0.01.05 or a later version.
- Update Rv260 Firmware to 1.0.01.05 or a later version.
- Read the advisory on tools.cisco.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco Small Business RV Series Router Firmware | Not specified in the record | Not stated |
| Cisco | Rv160 Firmware | before 1.0.01.05 | 1.0.01.05 |
| Cisco | Rv160w Firmware | before 1.0.01.05 | 1.0.01.05 |
| Cisco | Rv260 Firmware | before 1.0.01.05 | 1.0.01.05 |
| Cisco | Rv260p Firmware | before 1.0.01.05 | 1.0.01.05 |
| Cisco | Rv260w Firmware | before 1.0.01.05 | 1.0.01.05 |
| Cisco | Rv340 Firmware | before 1.0.03.26 | 1.0.03.26 |
| Cisco | Rv340w Firmware | before 1.0.03.26 | 1.0.03.26 |
| Cisco | Rv345 Firmware | before 1.0.03.26 | 1.0.03.26 |
| Cisco | Rv345p Firmware | before 1.0.03.26 | 1.0.03.26 |
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
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- 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:N/UI:N/S:C/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.0 | Critical | CNA (cisco.com) |
| CVSS 3.1 | 10.0 | Critical | NVD |
Official description
Multiple vulnerabilities in Cisco Small Business RV160, RV260, RV340, and RV345 Series Routers could allow an unauthenticated, remote attacker to execute arbitrary code or cause a denial of service (DoS) condition on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in an OS Command
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Improper Neutralization of Special Elements used in an OS Command vulnerabilities (CWE-78)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Cisco Small Business RV Series Router Firmware
- 9.1 Critical severity
- 9.1 Critical severity
- 9.1 Critical severity
- 9.1 Critical severity
- 7.2 High severity
- 8.8 High severity
Recent Improper Neutralization of Special Elements used in an OS Command vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.2 High severity
- 8.8 High severity
- 7.2 High severity
Spotted an error? Tell us.