RubyGems: Gem signature forgery

Summary Inconsistencies in how gem processes gem files make it possible to reuse a signature from an existing signed gem and apply it to arbitrary contents. The forged gem will install even with -P HighSecurity. The attached file multijson-1.12.2.gem is a forged version of the genuine...

RubyGems: Installing a crafted gem package may create or overwrite files

There is no check for name field in metadata.gz. By assigning a maliciously crafted string like ../../../../../any/where to the field, an attacker can create an arbitrary file out of the directory of the gem, or even replace an existing file with a malicious file. Proof of Concept 1: Create a fil...