A vulnerability in the web-based interface of Cisco Webex Teams could allow an authenticated, remote attacker to conduct cross-site scripting attacks.
The vulnerability is due to improper validation of usernames. An attacker could exploit this vulnerability by creating an account that contains malicious HTML or script content and joining a space using the malicious account name. A successful exploit could allow the attacker to conduct cross-site scripting attacks and potentially gain access to sensitive browser-based information.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Weakness
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as “<”, “>”, and “&” that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.
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.
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