CVE-2016-4435 in Director VM
Summary
by MITRE
An endpoint of the Agent running on the BOSH Director VM with stemcell versions prior to 3232.6 and 3146.13 may allow unauthenticated clients to read or write blobs or cause a denial of service attack on the Director VM. This vulnerability requires that the unauthenticated clients guess or find a URL matching an existing GUID.
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Analysis
by VulDB Data Team • 10/03/2020
The vulnerability described in CVE-2016-4435 represents a significant security flaw in the BOSH Director VM's agent component that affects specific stemcell versions. This issue stems from improper authentication mechanisms within the Director's endpoint handling, creating a scenario where unauthorized parties can potentially access sensitive data or disrupt system operations. The vulnerability specifically impacts environments using stemcell versions prior to 3232.6 and 3146.13, indicating that it was introduced in earlier releases and subsequently patched in later versions of the BOSH ecosystem.
The technical nature of this vulnerability involves a lack of proper authentication checks on certain endpoints within the BOSH Director's agent service. Attackers can exploit this weakness by crafting requests to specific URLs that correspond to existing globally unique identifiers or GUIDs within the system. This approach essentially allows for a form of brute force or guessing attack where malicious actors attempt to discover valid GUIDs to access restricted functionality. The vulnerability creates three primary attack vectors: unauthorized data reading, unauthorized data writing, and denial of service conditions that can compromise the availability of the Director VM service.
The operational impact of this vulnerability extends beyond simple unauthorized access as it can lead to complete system compromise or service disruption. An attacker who successfully guesses or discovers valid GUIDs can potentially read sensitive configuration data, modify critical system parameters, or flood the system with requests to cause denial of service conditions. This type of vulnerability particularly affects cloud infrastructure management systems where the BOSH Director serves as a central orchestration point for deploying and managing cloud workloads. The attack surface becomes more dangerous when considering that BOSH Directors typically manage critical infrastructure components and may contain sensitive deployment information.
From a cybersecurity perspective, this vulnerability aligns with CWE-287 which addresses improper authentication issues, and can be mapped to ATT&CK technique T1190 for exploiting vulnerabilities in software applications. The weakness demonstrates poor input validation and insufficient access controls, particularly in the context of cloud infrastructure management systems. Organizations using affected BOSH versions face potential exposure to attackers who can leverage this vulnerability to gain unauthorized access to their cloud deployment infrastructure, potentially leading to data breaches or service interruptions that could affect multiple deployed applications and services.
The recommended mitigation strategy involves upgrading to stemcell versions 3232.6 or 3146.13 and later, which contain the necessary security patches to address the authentication flaws. Additionally, organizations should implement network segmentation to limit access to the BOSH Director endpoints and consider implementing additional monitoring for suspicious URL access patterns. Security teams should also conduct thorough inventory checks to identify all affected systems and ensure proper patch management procedures are in place to prevent similar vulnerabilities from emerging in the future.