CVE-2016-4924 in Junos
Summary
by MITRE
An incorrect permissions vulnerability in Juniper Networks Junos OS on vMX may allow local unprivileged users on a host system read access to vMX or vPFE images and obtain sensitive information contained in them such as private cryptographic keys. This issue was found during internal product security testing. Juniper SIRT is not aware of any malicious exploitation of this vulnerability. No other Juniper Networks products or platforms are affected by this issue. Affected releases are Juniper Networks Junos OS 15.1 prior to 15.1F5; 14.1 prior to 14.1R8
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Analysis
by VulDB Data Team • 01/03/2023
The vulnerability identified as CVE-2016-4924 represents a critical permissions flaw within Juniper Networks Junos OS operating on vMX virtualized platforms. This issue stems from improper access controls that permit unprivileged local users to gain unauthorized read access to sensitive system components. The vulnerability specifically targets the vMX (virtual Machine) and vPFE (virtual Packet Forwarding Engine) images, which contain critical cryptographic materials and system configuration data. During routine internal security assessments, this weakness was discovered, highlighting the importance of comprehensive testing protocols in identifying potential attack vectors within complex networking infrastructure.
The technical implementation of this vulnerability involves flawed file system permissions that allow local users to access memory segments containing sensitive information. This misconfiguration enables attackers to extract private cryptographic keys, system images, and other confidential data from the virtualized environment. The vulnerability exists at the operating system level within Junos OS, specifically affecting versions prior to 15.1F5 and 14.1R8, where proper access controls were not adequately enforced. The flaw represents a classic case of insufficient privilege separation, where local users can bypass normal security boundaries to access restricted system resources.
The operational impact of this vulnerability extends beyond simple information disclosure, as the compromised cryptographic keys could potentially be used to impersonate network devices or decrypt sensitive communications. Attackers could leverage this access to gain deeper insights into the network infrastructure, potentially leading to more sophisticated attacks including man-in-the-middle operations or unauthorized device management access. The vulnerability's local nature means that exploitation requires physical or logical access to the compromised system, but once achieved, it provides a persistent backdoor for information extraction and potential further compromise.
Security practitioners should implement immediate mitigations including updating affected Junos OS versions to the patched releases 15.1F5 and 14.1R8, which contain proper access control mechanisms. System administrators should also review and tighten local user permissions, implement monitoring for unauthorized file access attempts, and conduct thorough security audits of virtualized environments. This vulnerability aligns with CWE-276, which addresses improper file permissions, and maps to ATT&CK technique T1005 for data from local system. Organizations should also consider implementing network segmentation and privilege escalation controls to limit potential lateral movement if such vulnerabilities are exploited in other parts of their infrastructure.
The discovery of this vulnerability underscores the critical importance of maintaining up-to-date security patches, particularly in virtualized environments where multiple system components share underlying resources. This case demonstrates how seemingly minor permission flaws can have significant implications for cryptographic security and overall system integrity. Regular security assessments and vulnerability management processes are essential to identify and remediate such issues before they can be exploited by malicious actors. The lack of documented malicious exploitation serves as a warning that such vulnerabilities may be actively targeted by threat actors who have not yet publicly disclosed their activities against this specific flaw.