Cisco Small Business Routers Improper Input Validation
CVE-2019-1652 is a high-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 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. CISA added it to the Known Exploited Vulnerabilities catalogue on March 3, 2022, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Rv320 Firmware to 1.4.2.22 or a later version.
- Update Rv325 Firmware to 1.4.2.22 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on tools.cisco.com for workarounds and exact fixed builds.
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 | Rv320 Firmware | 1.4.2.15 up to, but not including, 1.4.2.22 | 1.4.2.22 |
| Cisco | Rv325 Firmware | 1.4.2.15 up to, but not including, 1.4.2.22 | 1.4.2.22 |
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 system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.2 | High | NVD |
| CVSS 3.0 | 7.2 | High | CNA (cisco.com) |
| CVSS 2.0 | 9.0 | High | NVD |
Official description
A vulnerability in the web-based management interface of Cisco Small Business RV320 and RV325 Dual Gigabit WAN VPN Routers could allow an authenticated, remote attacker with administrative privileges on an affected device to execute arbitrary commands. The vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending malicious HTTP POST requests to the web-based management interface of an affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying Linux shell as root. Cisco has released firmware updates that address this vulnerability.
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.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- packetstormsecurity.com/files/152305/Cisco-RV320-RV325-Unauthenticated-Remote-Code-Execution.htmlThird Party Advisory, VDB Entry
- securityfocus.com/bid/106728Third Party Advisory, VDB Entry
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-1652US Government Resource
Technical write-ups (may include proof of concept)
- packetstormsecurity.com/files/152262/Cisco-RV320-Command-Injection.htmlExploit, Third Party Advisory, VDB Entry
- seclists.org/fulldisclosure/2019/Mar/61Exploit, Mailing List, Third Party Advisory
- seclists.org/bugtraq/2019/Mar/55Exploit, Mailing List, Third Party Advisory
- exploit-db.com/exploits/46243/Exploit, Third Party Advisory, VDB Entry
- exploit-db.com/exploits/46655/Exploit, Third Party Advisory, VDB Entry
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
- 7.2 High severity
- 8.1 High severity
- 9.8 Critical severity
- 9.8 Critical severity
Dasan GPON Routers Command Injection Exploited
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