CVE-2016-0057 in Office
Summary
by MITRE
Microsoft Office 2007 SP3, 2010 SP2, 2013 SP1, and 2016 does not properly sign an unspecified binary file, which allows local users to gain privileges via a Trojan horse file with a crafted signature, aka "Microsoft Office Security Feature Bypass Vulnerability."
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Analysis
by VulDB Data Team • 07/09/2022
The vulnerability identified as CVE-2016-0057 represents a critical security flaw in Microsoft Office versions 2007 SP3, 2010 SP2, 2013 SP1, and 2016 where the software fails to properly validate the digital signature of an unspecified binary file. This weakness stems from insufficient signature verification mechanisms within the Office application's security framework, creating a pathway for malicious actors to exploit the system through crafted Trojan horse files. The vulnerability specifically targets the security feature bypass aspect, allowing attackers to circumvent the normal authentication and authorization processes that should prevent unauthorized code execution. This issue falls under the broader category of software signing and verification failures that can lead to privilege escalation attacks.
The technical implementation of this vulnerability involves the manipulation of binary file signatures within Microsoft Office applications, where the software's signature validation process is inadequate to detect malicious modifications. Attackers can create specially crafted files that appear legitimate to the Office security system but contain hidden malicious code that executes with elevated privileges. The flaw operates at the kernel level where Office applications interact with the operating system's security mechanisms, making it particularly dangerous as it can bypass standard user access controls and execute code with administrative privileges. This type of vulnerability is classified as a security feature bypass according to the Common Weakness Enumeration framework, specifically relating to insufficient verification of signatures and certificates.
The operational impact of CVE-2016-0057 extends beyond simple privilege escalation to encompass broader system compromise and data exfiltration capabilities. Local attackers who successfully exploit this vulnerability can gain elevated system privileges, allowing them to install malware, modify system files, and potentially establish persistent backdoors within the compromised environment. The vulnerability is particularly concerning in enterprise environments where Office applications are widely used, as it can serve as a foothold for lateral movement and broader network infiltration. Security researchers have documented similar patterns in the MITRE ATT&CK framework where adversaries leverage application security flaws to gain elevated privileges and maintain persistence.
Mitigation strategies for this vulnerability require immediate patching of affected Office versions through Microsoft's security updates, as the primary solution involves correcting the signature validation mechanism. Organizations should implement comprehensive endpoint protection solutions that monitor for suspicious file execution patterns and maintain strict application whitelisting policies to prevent unauthorized code execution. Network segmentation and privilege separation can help limit the potential impact if exploitation occurs, while regular security audits should verify that all Office installations are properly updated and that signature validation mechanisms are functioning correctly. Additionally, user education programs should emphasize the importance of verifying file sources and avoiding suspicious attachments that might exploit this particular vulnerability.