CVE-2023-20188

A vulnerability in the web-based management interface of Cisco Small Business 200 Series Smart Switches, Cisco Small Business 300 Series Managed Switches, and Cisco Small Business 500 Series Stackable Managed Switches could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the interface on an affected device. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by persuading a user of an affected interface to view a page containing malicious HTML or script content. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information. To exploit this vulnerability, the attacker would need to have valid credentials to access the web-based management interface of the affected device. Cisco has not released software updates to address this vulnerability.

Weakness

The product does not neutralize or incorrectly neutralizes user-controlled input for alternate script syntax.

Affected Software

Potential Mitigations

• Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
• The problem of inconsistent output encodings often arises in web pages. If an encoding is not specified in an HTTP header, web browsers often guess about which encoding is being used. This can open up the browser to subtle XSS attacks.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/199.html

References

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smb-sxss-OPYJZUmE
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-smb-sxss-OPYJZUmE