CVE-2019-8323

Vulnerability

Description

CVE-2019-8323 is an escape sequence injection vulnerability in RubyGems, affecting versions 2.6 through 3.0.2. The flaw resides in the Gem::GemcutterUtilities#with_response method, which outputs the API response directly to stdout without sanitization. If an attacker can modify the API response (e.g., through a man-in-the-middle attack or a compromised gem server), they can inject arbitrary escape sequences into the terminal output [1][2].

Attack

Vector and Requirements

Exploitation requires the attacker to control or modify the API response that RubyGems processes. This could occur when the gem client communicates with a malicious or compromised gem server, or through network-level manipulation. No additional authentication is needed beyond the normal gem commands that invoke the API (e.g., gem push, gem owner). The user must be viewing the output in a terminal that interprets escape sequences [2][3].

Impact

Successful injection of escape sequences can lead to terminal manipulation, potentially allowing the attacker to execute arbitrary commands on the user's terminal, overwrite display content, or deceive the user into performing unintended actions. This is similar to other terminal escape sequence vulnerabilities and can be leveraged for further compromise [2].

Mitigation

The vulnerability is fixed in RubyGems version 3.0.3 and 2.7.8. Users unable to upgrade to these versions can apply a patch for RubyGems 2.6. It is strongly recommended to upgrade to the latest stable version to mitigate this and other related vulnerabilities disclosed in March 2019 [2].