masahiro331/cve-2020-8277Proof-of-concept exploit for CVE-2020-8277, a Node.js DNS resolver denial-of-service vulnerability triggered by large record responses, with Docker-based reproduction environment.
For educational purposes only.
# clone this repository
$ git clone https://github.com/masahiro331/CVE-2020-8277
# run bind
$ docker build -t bind-local ./bind
# Need TCP fallback
$ docker run --rm --name bind -it -p 53:53 -p 53:53/udp bind
# use "< v15.2.1" version
# If you use fixed version, build node.
$ git clone https://github.com/nodejs/node
$ git checkout df211208c0
$ ./configure
$ make -j8
$ make install
# Run PoC
$ node main.js
See Reference for the details.
https://nodejs.org/en/blog/vulnerability/november-2020-security-releases/
The advisory states that resolving a hostname that returns a large number of records will result in DoS.
The vulnerability has read out of memory error.
Affected line.
https://github.com/nodejs/node/blob/1fd2c8142b611baadc973947b83c0863cb003d9d/src/cares_wrap.cc#L764