Cyber Risks · PortSwigger Research

Exploiting prototype pollution in Node without the filesystem

Summary: PortSwigger researcher Gareth Heyes documented a new server-side prototype pollution exploitation technique that uses Node's --import command line flag, available from Node 19.0.0, to load a data: URL module and execute arbitrary JavaScript without placing any file on the filesystem. Heyes reported the NODE_OPTIONS behavior to the Node developers, who decided it was "not an entrypoint security issue" and did not violate their threat model.

Why it matters: The usual SSPP-to-RCE path through fork() depends on --require and the filesystem or environment variables; --import removes the local-file requirement, so a leader whose detection assumes file drops will miss this route entirely.

Read the original at PortSwigger Research ↗

Topics
Vulnerabilities & Patching
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