CVE-2011-4103 in Django Piston
Summary
by MITRE
emitters.py in Django Piston before 0.2.3 and 0.2.x before 0.2.2.1 does not properly deserialize YAML data, which allows remote attackers to execute arbitrary Python code via vectors related to the yaml.load method.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 04/03/2022
The vulnerability identified as CVE-2011-4103 represents a critical remote code execution flaw in Django Piston, a Python web framework component used for building RESTful APIs. This issue specifically affects versions prior to 0.2.3 and 0.2.x prior to 0.2.2.1, where the emitters.py module fails to properly handle YAML data deserialization. The flaw stems from the insecure usage of the yaml.load() method which can be manipulated by attackers to execute arbitrary Python code on the target system. The vulnerability creates a direct pathway for remote attackers to gain unauthorized access and potentially compromise the entire application server.
The technical exploitation of this vulnerability occurs through the improper deserialization of YAML data structures. When Django Piston processes incoming YAML requests through the emitters.py module, it uses the yaml.load() function without proper sanitization or restriction of the loaded data types. This allows attackers to craft malicious YAML payloads containing Python object references that get executed during the deserialization process. The yaml.load() method in Python is inherently dangerous when used without proper restrictions because it can instantiate arbitrary Python objects, including those that may execute system commands or access sensitive resources. This behavior aligns with CWE-502, which specifically addresses deserialization of untrusted data, and represents a classic example of insecure deserialization that can lead to remote code execution.
The operational impact of this vulnerability is severe and far-reaching for any system utilizing affected versions of Django Piston. Attackers can leverage this flaw to execute arbitrary commands on the server hosting the vulnerable application, potentially gaining complete control over the system. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring authentication or physical access to the target environment. This vulnerability effectively transforms the API endpoint into a backdoor for malicious actors, enabling them to perform data exfiltration, system compromise, or further lateral movement within the network infrastructure. Organizations using vulnerable versions of Django Piston face significant risk of data breaches, system compromise, and potential regulatory compliance violations.
Mitigation strategies for CVE-2011-4103 focus primarily on immediate version upgrades to patched releases of Django Piston. The most effective remediation involves upgrading to Django Piston version 0.2.3 or later for the 0.2.x series, or ensuring that the affected 0.2.2.1 version is properly implemented. Organizations should also consider implementing network-level restrictions to limit access to API endpoints that utilize the vulnerable emitters.py module. Additionally, application-level security measures such as input validation and sanitization should be implemented to reduce the attack surface. The ATT&CK framework categorizes this vulnerability under T1059.001 for execution through Python commands, and T1078 for valid accounts as it can be exploited through legitimate API access points. Security teams should also implement monitoring and logging for unusual API activity patterns that might indicate exploitation attempts.