During some analysis today on npm's node-tar
package I came across the folder creation process, Basicly if you provide node-tar with a path like this ./a/b/c/foo.txt
it would create every folder and sub-folder here a, b and c until it reaches the last folder to create foo.txt
, In-this case I noticed that there's no validation at all on the amount of folders being created, that said we're actually able to CPU and memory consume the system running node-tar and even crash the nodejs client within few seconds of running it using a path with too many sub-folders inside
You can reproduce this issue by downloading the tar file I provided in the resources and using node-tar to extract it, you should get the same behavior as the video
Here's a video show-casing the exploit:
Denial of service by crashing the nodejs client when attempting to parse a tar archive, make it run out of heap memory and consuming server CPU and memory resources
This report was originally reported to GitHub bug bounty program, they asked me to report it to you a month ago