CVE-2015-5242 in Swift-on-File
Summary
by MITRE
OpenStack Swift-on-File (aka Swiftonfile) does not properly restrict use of the pickle Python module when loading metadata, which allows remote authenticated users to execute arbitrary code via a crafted extended attribute (xattrs).
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Analysis
by VulDB Data Team • 06/27/2022
OpenStack Swift-on-File represents a storage solution that bridges traditional file systems with OpenStack Swift's object storage capabilities, enabling seamless integration of local file systems into cloud environments. The vulnerability identified as CVE-2015-5242 resides within this integration layer where the system improperly handles metadata loading operations through the Python pickle module. This flaw occurs when the system processes extended attributes (xattrs) that contain serialized Python objects, creating a critical security gap that can be exploited by authenticated attackers with access to the storage system.
The technical root cause of this vulnerability stems from the insecure use of Python's pickle module, which is designed for serializing and deserializing Python objects but lacks proper input validation and sanitization mechanisms. When Swift-on-File processes extended attributes containing pickle-formatted data, it fails to implement proper restrictions or validation checks before deserializing these objects. This behavior directly maps to CWE-502, which categorizes deserialization of untrusted data as a critical security weakness. The vulnerability allows attackers to craft malicious extended attributes that, when processed by the system, trigger arbitrary code execution through the pickle deserialization mechanism.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to escalate privileges and potentially compromise the entire storage infrastructure. Since the vulnerability requires only authenticated access to the storage system, it represents a significant risk in environments where multiple users or applications interact with the Swift-on-File service. Attackers can leverage this weakness to execute malicious payloads that could lead to data exfiltration, system compromise, or further lateral movement within the network. The attack vector specifically targets the metadata processing pipeline where extended attributes are handled, making it particularly dangerous as it operates within the legitimate system processing paths.
Security professionals should implement multiple layers of mitigation strategies to address this vulnerability effectively. The primary recommendation involves disabling or restricting the use of pickle serialization within the Swift-on-File components, replacing it with safer serialization formats such as JSON or XML that do not pose the same arbitrary code execution risks. Additionally, implementing strict input validation and sanitization for all extended attributes processed by the system can prevent malicious payloads from being accepted. Network segmentation and access controls should be strengthened to limit the scope of potential exploitation, while regular security audits and monitoring of extended attribute usage patterns can help detect anomalous behavior. Organizations should also consider implementing the principle of least privilege for system users and applications accessing the Swift-on-File service, ensuring that only necessary entities have the ability to manipulate extended attributes. The ATT&CK framework categorizes this vulnerability under T1059.001 for command and scripting interpreter, highlighting the execution of malicious code through interpreted languages, and T1068 for exploit for privilege escalation, emphasizing the potential for privilege abuse once initial access is gained through this vulnerability.