CVE-2013-6795 in Windows Agent
Summary
by MITRE
The Updater in Rackspace Openstack Windows Guest Agent for XenServer before 1.2.6.0 allows remote attackers to execute arbitrary code via a crafted serialized .NET object to TCP port 1984, which triggers the download and extraction of a ZIP file that overwrites the Agent service binary.
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Analysis
by VulDB Data Team • 05/19/2017
The vulnerability described in CVE-2013-6795 represents a critical remote code execution flaw within the Rackspace Openstack Windows Guest Agent for XenServer. This issue affects versions prior to 1.2.6.0 and demonstrates a classic deserialization vulnerability that enables attackers to execute arbitrary code on compromised systems. The vulnerability specifically targets the Updater component of the guest agent, which operates on TCP port 1984, making it accessible over the network and exploitable by remote adversaries.
The technical exploitation mechanism involves crafting a malicious serialized .NET object that gets processed by the vulnerable Updater service. When this malformed object is sent to TCP port 1984, the service deserializes the object without proper validation, leading to arbitrary code execution. This deserialization flaw directly maps to CWE-502, which categorizes insecure deserialization as a significant security weakness. The attack chain continues with the execution of a download and extraction process that overwrites the legitimate Agent service binary with malicious content, effectively enabling persistent compromise of the target system.
The operational impact of this vulnerability extends beyond immediate code execution capabilities to encompass complete system compromise and potential lateral movement within cloud environments. Since the affected agent runs within virtualized Windows environments managed by XenServer, successful exploitation could provide attackers with full control over guest virtual machines and potentially enable them to access underlying infrastructure resources. The vulnerability's presence in a cloud guest agent makes it particularly dangerous as it can be leveraged to maintain persistence, establish command and control channels, and escalate privileges within cloud deployments.
This vulnerability aligns with several ATT&CK techniques including T1059.001 for command and scripting interpreter, T1078 for valid accounts, and T1566 for spearphishing attachments, as the exploitation typically involves sending malicious serialized objects that trigger the download of compromised ZIP files. The attack surface is particularly concerning in cloud environments where multiple virtual machines may be running the vulnerable agent version, potentially allowing for mass compromise. Organizations using Rackspace Openstack Windows Guest Agent for XenServer should prioritize immediate remediation through version updates, network segmentation to restrict access to TCP port 1984, and implementation of proper input validation and secure deserialization practices to prevent similar vulnerabilities from being exploited in the future.