CVE-2019-8323 in RubyGems
Summary
by MITRE
An issue was discovered in RubyGems 2.6 and later through 3.0.2. Gem::GemcutterUtilities#with_response may output the API response to stdout as it is. Therefore, if the API side modifies the response, escape sequence injection may occur.
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Analysis
by VulDB Data Team • 10/06/2023
The vulnerability identified as CVE-2019-8323 resides within RubyGems version 2.6 through 3.0.2, specifically affecting the Gem::GemcutterUtilities#with_response method. This flaw represents a critical security concern that stems from improper handling of API responses within the RubyGems package management system. The vulnerability allows for potential escape sequence injection when the API response contains unescaped characters that could be interpreted by terminal emulators or command-line interfaces, leading to unintended execution of commands or manipulation of output display.
The technical root cause of this vulnerability lies in the method's failure to sanitize or properly escape API responses before outputting them to standard output. When RubyGems processes gem-related operations through the Gemcutter API, the with_response method directly outputs the raw API response data without adequate filtering or encoding. This behavior creates an environment where malicious API responses could contain escape sequences that manipulate terminal behavior, potentially enabling attackers to execute arbitrary commands or alter the display of command-line interfaces. The vulnerability is particularly dangerous because it operates at the point of API interaction, where legitimate system operations meet external data sources.
The operational impact of CVE-2019-8323 extends beyond simple output manipulation, as it can enable attackers to perform command injection attacks through carefully crafted API responses. An attacker who can influence the API endpoint or intercept communication between RubyGems and the Gemcutter service could craft malicious responses containing escape sequences that, when processed by the with_response method, could execute unintended commands on the victim's system. This vulnerability affects developers and system administrators who rely on RubyGems for package management, potentially compromising entire development environments or production systems where Ruby applications are deployed. The risk is amplified because the vulnerability operates silently in the background during normal gem operations, making detection difficult until exploitation occurs.
Security mitigations for this vulnerability should focus on implementing proper input sanitization and output escaping mechanisms within the Gem::GemcutterUtilities#with_response method. The recommended approach involves adding comprehensive filtering to remove or escape potentially dangerous characters from API responses before output processing. Organizations should upgrade to RubyGems versions that have patched this vulnerability, as the maintainers have addressed the issue through proper response sanitization. Additionally, network-level monitoring should be implemented to detect unusual API response patterns that might indicate attempted exploitation. This vulnerability aligns with CWE-116, which addresses the improper handling of escape sequences, and could be leveraged under ATT&CK technique T1059.001 for command and scripting interpreter execution. System administrators should also consider implementing network segmentation and API access controls to limit exposure, particularly in environments where RubyGems interacts with untrusted API endpoints. The patching process requires careful verification to ensure that response sanitization does not break legitimate functionality while effectively mitigating the escape sequence injection risk.