Microsoft has disclosed a serious security vulnerability in its Office suite, identified as CVE-2024-38200, which poses a risk of sensitive data theft. The flaw affects multiple versions of Microsoft Office, including Office 2016, Office 2019, Office LTSC 2021, and Microsoft 365 Apps for Enterprise, across both 32-bit and 64-bit systems. With a CVSS score of 7.5, this spoofing vulnerability is classified under CWE-200, highlighting its potential to expose confidential information to unauthorized actors.
In a typical attack scenario, cybercriminals could exploit this vulnerability by hosting a malicious website or compromising an existing site to deliver a specially crafted file. The attacker would then need to deceive the user into visiting the website and opening the file, often through phishing emails or instant messages. This reliance on user interaction is a critical factor in the exploit’s effectiveness, making user awareness and caution essential in preventing attacks.
Although Microsoft has assessed the likelihood of widespread exploitation as “less likely,” the company has proactively addressed the issue. An alternative fix was released on July 30, 2024, through Feature Flighting, providing temporary protection for all supported Office versions. A formal patch is scheduled for release on August 13, 2024, which users are strongly encouraged to apply for comprehensive protection against this vulnerability.
To further mitigate risks, Microsoft recommends several security strategies: restricting NTLM traffic by configuring network security policies, adding high-value accounts to the Protected Users Security Group to prevent NTLM usage, and blocking outbound traffic on TCP port 445/SMB using firewalls. The vulnerability’s discovery is credited to researchers Jim Rush from PrivSec Consulting and Metin Yunus Kandemir from Synack Red Team, who will discuss these findings further at DEF CON 2024. Microsoft continues to emphasize the importance of keeping systems updated and applying security patches promptly to safeguard against potential threats.
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