Know every vulnerabilitybefore it knows you.
DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.
GHSA-jg82-xh3w-rhxx
No affected components available
Impact
A __proto__ pollution vulnerability exists in synchrony versions before v2.4.4. Successful exploitation could lead to arbitrary code execution.
Summary
A __proto__ pollution vulnerability exists in the LiteralMap transformer allowing crafted input to modify properties in the Object prototype.
When executing in Node.js, due to use of the prettier module, defining a parser property on __proto__ with a path to a JS module on disk causes a require of the value which can lead to arbitrary code execution.
Patch
A fix has been released in deobfuscator@2.4.4.
Mitigation
- Upgrade synchrony to v2.4.4
- Launch node with the --disable-proto=delete or --disable-proto=throw flag
Proof of Concept
Craft a malicious input file named poc.js as follows:
// Malicious code to be run after this file is imported. Logs the result of shell command "dir" to the console.
console.log(require('child_process').execSync('dir').toString())
// Synchrony exploit PoC
{
var __proto__ = { parser: 'poc.js' }
}
Then, run synchrony poc.js from the same directory as the malicious file.
Credits
This vulnerability was found and disclosed by William Khem-Marquez.
The vulnerability requires local access to the device to be exploited. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
Browse More
Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.
Checkout DevGuard