A vulnerability in the messaging interface of Cisco Webex App, formerly Webex Teams, could allow an unauthenticated, remote attacker to manipulate links or other content within the messaging interface. This vulnerability exists because the affected software does not properly handle character rendering. An attacker could exploit this vulnerability by sending messages within the application interface. A successful exploit could allow the attacker to modify the display of links or other content within the interface, potentially allowing the attacker to conduct phishing or spoofing attacks.
Weakness
The UI has multiple interpretations of user input but does not prompt the user when it selects the less secure interpretation.
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Webex_teams |
Cisco |
* |
42.7 (excluding) |
Potential Mitigations
- Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
References