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JS: Improve Express middleware taint tracking #19784

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67aac7a
JS: add test cases for middleware property assignment tracking
Napalys Jun 16, 2025
da21a06
JS: add `_parsedUrl` as remote input source
Napalys Jun 16, 2025
060b98d
JS: enchance middleware taint tracking via local source
Napalys Jun 16, 2025
7252874
JS: add change note
Napalys Jun 16, 2025
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5 changes: 5 additions & 0 deletions javascript/ql/lib/change-notes/2025-06-16-middleware-express.md
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@@ -0,0 +1,5 @@
---
category: minorAnalysis
---
* Improved data flow tracking through middleware to handle default value and similar patterns.
* Added `req._parsedUrl` as a remote input source.
2 changes: 1 addition & 1 deletion javascript/ql/lib/semmle/javascript/Routing.qll
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Expand Up @@ -925,7 +925,7 @@ module Routing {
private DataFlow::Node getAnAccessPathRhs(Node base, int n, string path) {
// Assigned in the body of a route handler function, which is a middleware
exists(RouteHandler handler | base = handler |
result = AccessPath::getAnAssignmentTo(handler.getParameter(n).ref(), path) and
result = AccessPath::getAnAssignmentTo(handler.getParameter(n).ref(), path).getALocalSource() and
(
exists(handler.getAContinuationInvocation())
or
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2 changes: 1 addition & 1 deletion javascript/ql/lib/semmle/javascript/frameworks/Express.qll
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Expand Up @@ -620,7 +620,7 @@ module Express {
or
// `req.path`
kind = "url" and
this = ref.getAPropertyRead("path")
this = ref.getAPropertyRead(["path", "_parsedUrl"])
)
}

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32 changes: 32 additions & 0 deletions javascript/ql/test/query-tests/Security/CWE-918/RequestForgery.expected
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Expand Up @@ -6,6 +6,10 @@
| apollo.serverSide.ts:8:39:8:64 | get(fil ... => {}) | apollo.serverSide.ts:7:36:7:44 | { files } | apollo.serverSide.ts:8:43:8:50 | file.url | The $@ of this request depends on a $@. | apollo.serverSide.ts:8:43:8:50 | file.url | URL | apollo.serverSide.ts:7:36:7:44 | { files } | user-provided value |
| apollo.serverSide.ts:18:37:18:62 | get(fil ... => {}) | apollo.serverSide.ts:17:34:17:42 | { files } | apollo.serverSide.ts:18:41:18:48 | file.url | The $@ of this request depends on a $@. | apollo.serverSide.ts:18:41:18:48 | file.url | URL | apollo.serverSide.ts:17:34:17:42 | { files } | user-provided value |
| axiosInterceptors.serverSide.js:11:26:11:40 | userProvidedUrl | axiosInterceptors.serverSide.js:19:21:19:28 | req.body | axiosInterceptors.serverSide.js:11:26:11:40 | userProvidedUrl | The $@ of this request depends on a $@. | axiosInterceptors.serverSide.js:11:26:11:40 | userProvidedUrl | endpoint | axiosInterceptors.serverSide.js:19:21:19:28 | req.body | user-provided value |
| serverSide2.js:17:28:17:47 | axios.get(targetUrl) | serverSide2.js:10:25:10:31 | req.url | serverSide2.js:17:38:17:46 | targetUrl | The $@ of this request depends on a $@. | serverSide2.js:17:38:17:46 | targetUrl | URL | serverSide2.js:10:25:10:31 | req.url | user-provided value |
| serverSide2.js:20:29:20:49 | axios.g ... etUrl1) | serverSide2.js:9:43:9:56 | req._parsedUrl | serverSide2.js:20:39:20:48 | targetUrl1 | The $@ of this request depends on a $@. | serverSide2.js:20:39:20:48 | targetUrl1 | URL | serverSide2.js:9:43:9:56 | req._parsedUrl | user-provided value |
| serverSide2.js:23:29:23:49 | axios.g ... etUrl2) | serverSide2.js:22:24:22:30 | req.url | serverSide2.js:23:39:23:48 | targetUrl2 | The $@ of this request depends on a $@. | serverSide2.js:23:39:23:48 | targetUrl2 | URL | serverSide2.js:22:24:22:30 | req.url | user-provided value |
| serverSide2.js:26:29:26:49 | axios.g ... etUrl3) | serverSide2.js:11:24:11:30 | req.url | serverSide2.js:26:39:26:48 | targetUrl3 | The $@ of this request depends on a $@. | serverSide2.js:26:39:26:48 | targetUrl3 | URL | serverSide2.js:11:24:11:30 | req.url | user-provided value |
| serverSide.js:18:5:18:20 | request(tainted) | serverSide.js:14:29:14:35 | req.url | serverSide.js:18:13:18:19 | tainted | The $@ of this request depends on a $@. | serverSide.js:18:13:18:19 | tainted | URL | serverSide.js:14:29:14:35 | req.url | user-provided value |
| serverSide.js:20:5:20:24 | request.get(tainted) | serverSide.js:14:29:14:35 | req.url | serverSide.js:20:17:20:23 | tainted | The $@ of this request depends on a $@. | serverSide.js:20:17:20:23 | tainted | URL | serverSide.js:14:29:14:35 | req.url | user-provided value |
| serverSide.js:24:5:24:20 | request(options) | serverSide.js:14:29:14:35 | req.url | serverSide.js:23:19:23:25 | tainted | The $@ of this request depends on a $@. | serverSide.js:23:19:23:25 | tainted | URL | serverSide.js:14:29:14:35 | req.url | user-provided value |
Expand Down Expand Up @@ -61,6 +65,18 @@ edges
| axiosInterceptors.serverSide.js:19:21:19:28 | req.body | axiosInterceptors.serverSide.js:19:11:19:17 | { url } | provenance | |
| axiosInterceptors.serverSide.js:20:5:20:25 | userProvidedUrl | axiosInterceptors.serverSide.js:11:26:11:40 | userProvidedUrl | provenance | |
| axiosInterceptors.serverSide.js:20:23:20:25 | url | axiosInterceptors.serverSide.js:20:5:20:25 | userProvidedUrl | provenance | |
| serverSide2.js:9:34:9:63 | qs.pars ... .query) | serverSide2.js:19:24:19:51 | req.par ... rsedUrl | provenance | |
| serverSide2.js:9:43:9:56 | req._parsedUrl | serverSide2.js:9:34:9:63 | qs.pars ... .query) | provenance | |
| serverSide2.js:10:25:10:31 | req.url | serverSide2.js:16:23:16:41 | req.parsedQuery.url | provenance | |
| serverSide2.js:11:24:11:30 | req.url | serverSide2.js:25:24:25:41 | req.SomeObject.url | provenance | |
| serverSide2.js:16:11:16:41 | targetUrl | serverSide2.js:17:38:17:46 | targetUrl | provenance | |
| serverSide2.js:16:23:16:41 | req.parsedQuery.url | serverSide2.js:16:11:16:41 | targetUrl | provenance | |
| serverSide2.js:19:11:19:55 | targetUrl1 | serverSide2.js:20:39:20:48 | targetUrl1 | provenance | |
| serverSide2.js:19:24:19:51 | req.par ... rsedUrl | serverSide2.js:19:11:19:55 | targetUrl1 | provenance | |
| serverSide2.js:22:11:22:36 | targetUrl2 | serverSide2.js:23:39:23:48 | targetUrl2 | provenance | |
| serverSide2.js:22:24:22:30 | req.url | serverSide2.js:22:11:22:36 | targetUrl2 | provenance | |
| serverSide2.js:25:11:25:47 | targetUrl3 | serverSide2.js:26:39:26:48 | targetUrl3 | provenance | |
| serverSide2.js:25:24:25:41 | req.SomeObject.url | serverSide2.js:25:11:25:47 | targetUrl3 | provenance | |
| serverSide.js:14:9:14:52 | tainted | serverSide.js:18:13:18:19 | tainted | provenance | |
| serverSide.js:14:9:14:52 | tainted | serverSide.js:20:17:20:23 | tainted | provenance | |
| serverSide.js:14:9:14:52 | tainted | serverSide.js:23:19:23:25 | tainted | provenance | |
Expand Down Expand Up @@ -153,6 +169,22 @@ nodes
| axiosInterceptors.serverSide.js:19:21:19:28 | req.body | semmle.label | req.body |
| axiosInterceptors.serverSide.js:20:5:20:25 | userProvidedUrl | semmle.label | userProvidedUrl |
| axiosInterceptors.serverSide.js:20:23:20:25 | url | semmle.label | url |
| serverSide2.js:9:34:9:63 | qs.pars ... .query) | semmle.label | qs.pars ... .query) |
| serverSide2.js:9:43:9:56 | req._parsedUrl | semmle.label | req._parsedUrl |
| serverSide2.js:10:25:10:31 | req.url | semmle.label | req.url |
| serverSide2.js:11:24:11:30 | req.url | semmle.label | req.url |
| serverSide2.js:16:11:16:41 | targetUrl | semmle.label | targetUrl |
| serverSide2.js:16:23:16:41 | req.parsedQuery.url | semmle.label | req.parsedQuery.url |
| serverSide2.js:17:38:17:46 | targetUrl | semmle.label | targetUrl |
| serverSide2.js:19:11:19:55 | targetUrl1 | semmle.label | targetUrl1 |
| serverSide2.js:19:24:19:51 | req.par ... rsedUrl | semmle.label | req.par ... rsedUrl |
| serverSide2.js:20:39:20:48 | targetUrl1 | semmle.label | targetUrl1 |
| serverSide2.js:22:11:22:36 | targetUrl2 | semmle.label | targetUrl2 |
| serverSide2.js:22:24:22:30 | req.url | semmle.label | req.url |
| serverSide2.js:23:39:23:48 | targetUrl2 | semmle.label | targetUrl2 |
| serverSide2.js:25:11:25:47 | targetUrl3 | semmle.label | targetUrl3 |
| serverSide2.js:25:24:25:41 | req.SomeObject.url | semmle.label | req.SomeObject.url |
| serverSide2.js:26:39:26:48 | targetUrl3 | semmle.label | targetUrl3 |
| serverSide.js:14:9:14:52 | tainted | semmle.label | tainted |
| serverSide.js:14:19:14:42 | url.par ... , true) | semmle.label | url.par ... , true) |
| serverSide.js:14:29:14:35 | req.url | semmle.label | req.url |
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27 changes: 27 additions & 0 deletions javascript/ql/test/query-tests/Security/CWE-918/serverSide2.js
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@@ -0,0 +1,27 @@
const express = require('express');
const axios = require('axios');
const qs = require('qs');

const app = express();
const PORT = 3000;

app.use((req, res, next) => {
req.parsedQueryFromParsedUrl = qs.parse(req._parsedUrl.query); // $Source[js/request-forgery]
req.parsedQuery.url = req.url || {}; // $Source[js/request-forgery]
req.SomeObject.url = req.url; // $Source[js/request-forgery]
next();
});

app.get('/proxy', async (req, res) => {
const targetUrl = req.parsedQuery.url;
const response = await axios.get(targetUrl); // $Alert[js/request-forgery]

const targetUrl1 = req.parsedQueryFromParsedUrl.url;
const response1 = await axios.get(targetUrl1); // $Alert[js/request-forgery]

const targetUrl2 = req.url || {}; // $Source[js/request-forgery]
const response2 = await axios.get(targetUrl2); // $Alert[js/request-forgery]

const targetUrl3 = req.SomeObject.url || {};
const response3 = await axios.get(targetUrl3); // $Alert[js/request-forgery]
});