Critical Bug Reported in NPM Package With Millions of Downloads Weekly

A widely applied NPM deal termed ‘Pac-Resolver’ for the JavaScript programming language has been remediated with a repair for a higher-severity distant code execution vulnerability that could be abused to operate malicious code inside of Node.js apps anytime HTTP requests are sent.

The flaw, tracked as CVE-2021-23406, has a severity ranking of 8.1 on the CVSS vulnerability scoring program and influences Pac-Resolver variations just before 5…

A Proxy Vehicle-Configuration (PAC) file is a JavaScript function that establishes no matter if net browser requests ought to be routed right to the location or forwarded to a internet proxy server for a specified hostname. PAC data files are how proxy guidelines are distributed in organization environments.

“This offer is applied for PAC file guidance in Pac-Proxy-Agent, which is utilized in transform in Proxy-Agent, which then utilized all over the place as the regular go-to deal for HTTP proxy automobile-detection and configuration in Node.js,” Tim Perry mentioned in a compose-up released late last month. “It’s pretty well-liked: Proxy-Agent is made use of in all places from AWS’s CDK toolkit to the Mailgun SDK to the Firebase CLI.”

CVE-2021-23406 has to do with how Pac-Proxy-Agent will not sandbox PAC files properly, ensuing in a circumstance exactly where an untrusted PAC file can be abused to split out of the sandbox solely and run arbitrary code on the underlying functioning procedure. This, however, necessitates that the attacker possibly resides on the area network, has the capability to tamper with the contents of the PAC file, or chains it with a next vulnerability to change the proxy configuration.

“This is a perfectly-recognized attack towards the VM module, and it is effective simply because Node isn’t going to isolate the context of the ‘sandbox’ fully, because it truly is not really hoping to offer severe isolation,” Perry said. “The fix is uncomplicated: use a genuine sandbox as a substitute of the VM created-in module.”

Crimson Hat, in an independent advisory, mentioned the vulnerable package deal is delivered with its Sophisticated Cluster Administration for Kubernetes solution, but noted it is “presently not mindful of the vector to cause the vulnerability in the influenced element, on top of that the affected part is secured by person authentication reducing the likely effects of this vulnerability.”

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