An attacker is able to craft a request that results in an HTTP 301 (redirect) to an entirely different domain.
A request for: http://some.server.com//nodesecurity.org/%2e%2e would result in a 301 to //nodesecurity.org/%2e%2e which most browsers treat as a proper redirect as // is translated into the current schema being used.
Mitigating factor:
In order for this to work, st must be serving from the root of a server (/) rather than the typical sub directory (/static/) and the redirect URL will end with some form of URL encoded .. ("%2e%2e", "%2e.", ".%2e").
Overview*
st is a module for serving static files.
An attacker is able to craft a request that results in an HTTP 301 (redirect) to an entirely different domain.
A request for: http://some.server.com//nodesecurity.org/%2e%2e would result in a 301 to //nodesecurity.org/%2e%2e which most browsers treat as a proper redirect as // is translated into the current schema being used.
Mitigating factor:
In order for this to work, st must be serving from the root of a server (/) rather than the typical sub directory (/static/) and the redirect URL will end with some form of URL encoded .. ("%2e%2e", "%2e.", ".%2e").
Code example (provided by Xin Gao):
[example.js]
var st = require('st') var http = require('http') http.createServer(st(process.cwd())).listen(1337) $ curl -v http://localhost:1337//cve.mitre.com/%2e%2e
Remediation
Upgrade to v1.2.2 or later.