Cisco TelePresence Video Communication Server…: Improper Neutralization of Special Elements used in a Command
CVE-2023-20209 is a high-severity improper neutralization of special elements used in a command vulnerability in Cisco TelePresence Video Communication Server (VCS) Expressway 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. Affected Cisco TelePresence Video Communication Server (VCS) Expressway versions: X8.5.1; X8.5.3; X8.5, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 39.5% chance of exploitation within 30 days, which is in the top 1.37% of all scored CVEs.
EPSS places it among the vulnerabilities most likely to be exploited soon.
What to do
- Update Telepresence Video Communication Server to 14.3.1 or a later version.
- Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cisco | Cisco TelePresence Video Communication Server (VCS) Expressway | X8.5.1; X8.5.3; X8.5; X8.6.1; X8.6; X8.1.1; X8.1.2; X8.1; and 32 more ranges | Not stated |
| Cisco | Telepresence Video Communication Server | before 14.3.1 | 14.3.1 |
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 | 6.5 | Medium | CNA (cisco.com) |
| CVSS 3.1 | 7.2 | High | NVD |
Official description
A vulnerability in the web-based management interface of Cisco Expressway Series and Cisco TelePresence Video Communication Server (VCS) could allow an authenticated, remote attacker with read-write privileges on the application to perform a command injection attack that could result in remote code execution on an affected device. This vulnerability is due to insufficient validation of user-supplied 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 establish a remote shell with root privileges.
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 a Command
The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when 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.
- If possible, ensure that all external commands called from the program are statically created.
- Run time: Run time policy enforcement may be used in an allowlist fashion to prevent use of any non-sanctioned commands.
More Improper Neutralization of Special Elements used in a Command vulnerabilities (CWE-77)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Cisco TelePresence Video Communication Server (VCS) Expressway
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Neutralization of Special Elements used in a Command vulnerabilities
- 9.1 Critical severity
- 9.1 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
- 9.8 Critical severity
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