CVE-2013-1800 in crack
Summary
by MITRE
The crack gem 0.3.1 and earlier for Ruby does not properly restrict casts of string values, which might allow remote attackers to conduct object-injection attacks and execute arbitrary code, or cause a denial of service (memory and CPU consumption) by leveraging Action Pack support for (1) YAML type conversion or (2) Symbol type conversion, a similar vulnerability to CVE-2013-0156.
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Analysis
by VulDB Data Team • 01/02/2022
The crack gem vulnerability CVE-2013-1800 represents a critical security flaw in Ruby applications that utilize the crack gem version 0.3.1 or earlier for parsing and validating YAML data. This vulnerability stems from improper handling of string value casting operations within the gem's processing logic, creating a pathway for malicious actors to exploit the application's YAML type conversion mechanisms. The flaw specifically affects applications that rely on Action Pack's support for YAML type conversion, making it particularly dangerous in web applications that process user-supplied data through YAML parsing functionalities.
The technical implementation of this vulnerability occurs when the crack gem processes string inputs that contain specially crafted YAML payloads. The gem fails to properly validate or sanitize string values before attempting type conversions, allowing attackers to inject malicious objects that can be converted into arbitrary Ruby objects during the parsing process. This improper restriction of string casting operations creates an object-injection attack vector where attackers can manipulate the type conversion behavior to execute unintended code sequences. The vulnerability leverages the inherent trust that applications place in YAML parsing libraries, where legitimate YAML parsing operations become attack vectors when improperly validated input is processed.
The operational impact of CVE-2013-1800 extends beyond simple code execution to include potential denial of service conditions that can severely impact application availability. Attackers can exploit this vulnerability to consume excessive memory and CPU resources through carefully crafted payloads that trigger recursive or resource-intensive object creation patterns. The vulnerability's similarity to CVE-2013-0156 demonstrates a pattern of flaws in Ruby's YAML handling mechanisms where type conversion operations become attack surfaces. This makes the vulnerability particularly dangerous in high-traffic applications where a single exploit could lead to complete service disruption, while also enabling more sophisticated attacks that could compromise application integrity and confidentiality.
Mitigation strategies for CVE-2013-1800 require immediate remediation through version updates to crack gem 0.3.2 or later, which contain proper input validation and type conversion restrictions. Organizations should implement comprehensive input sanitization measures that validate all YAML data before processing, particularly when user-supplied content is involved. The vulnerability aligns with CWE-20: Improper Input Validation and follows attack patterns documented in the ATT&CK framework under T1190: Exploit Public-Facing Application, where attackers leverage application vulnerabilities to execute arbitrary code. Additionally, implementing proper sandboxing techniques and restricting YAML parsing capabilities to only trusted data sources can significantly reduce the attack surface. Security teams should also consider implementing web application firewalls and monitoring systems that can detect anomalous YAML parsing patterns that may indicate exploitation attempts.