Microsoft deserves credit for taking a significant security risk head-on. They pushed patches for an additional 67 undocumented vulnerabilities, most significantly addressing a critical remote code execution vulnerability, CVE-2025-33053. Another concrete vulnerability is due to the Web Distributed Authoring and Versioning (WebDAV) protocol. This protocol is widely adopted for remote file sharing and enterprise collaboration through endpoints. CVE-2025-33053 has a CVSS score of 8.8, signifying a critical and high risk level. This issue has been weaponized in the wild, placing users at risk.
In order to leverage CVE-2025-33053, victims need to establish a connection with a nefarious Server Message Block (SMB) server. This server is entirely under the attacker’s control. Once connected, attackers are able to run a reflective Kerberos relay attack on the account, allowing them to perform privilege escalation. Security researchers from Check Point first identified this vulnerability. Yet its power to exploit vulnerabilities makes it the newest and scariest headache for cybersecurity experts to combat.
Details of the Vulnerability
CVE-2025-33053 could pose a serious risk, considering the widespread deployment of WebDAV in enterprise environments. It lets attackers trick victims into clicking a specially designed link that starts the exploitation process.
When a victim clicks on the malicious URL, it triggers the execution of iediagcmd.exe. This program is a real Internet Explorer diagnostics tool. While this may appear to be a benign step, it actually paves the way for deploying the Horus Loader. It functions as a decoy PDF file, even while running the Horus Agent in the background. Horus Agent marks a major leap from the Apollo implant, integrating naturally into the Mythic command-and-control (C2) Paradigm.
“What makes this flaw particularly concerning is the widespread use of WebDAV in enterprise environments for remote file sharing and collaboration.” – Mike Walters, President and Co-Founder of Action1
The roadmap to exploitation shows low attack complexity, which means it would be easy for a threat actor to achieve. A successful exploitation grants an attacker the ability to escalate privileges and execute arbitrary commands at high-privileged NT AUTHORITY\SYSTEM privileges.
Implications of the Exploit
The consequences of CVE-2025-33053 are more than just vulnerability, it has become a launch point for advanced attacks. The vulnerability being used has been used to deliver Horus Agent, which greatly increases the attack capacity of the attacker.
The characteristics of this exploit mean that it is aimed at individual victims rather than the mass scale. According to Eli Smadja, research group manager at Check Point Research, “The activity appears to be highly targeted, affecting specific victims rather than being widespread.”
This vulnerability is a case study in the monumental task still ahead of organizations trying to secure their systems given constantly morphing threats.
“The principle behind the attack is that we coerced a Windows host to connect to our attack system via SMB and authenticate via Kerberos. The Kerberos ticket is then relayed back to the same host again via SMB. The resulting SMB session had high-privileged NT AUTHORITY\SYSTEM privileges that are sufficient to execute arbitrary commands.” – RedTeam Pentesting
To address these advancements, Microsoft has previously filed a lawsuit. They were proactive in releasing patches to minimize the risk associated with CVE-2025-33053 as well as other vulnerabilities. As a team, they fixed 67 vulnerabilities, 11 being critical. This emphasizes how critical it is for users to implement these changes as soon as possible.
Microsoft’s Response and Future Considerations
Microsoft credited Check Point researchers Alexandra Gofman and David Driker for their part in the discovery and reporting of CVE-2025-33053. Their research serves as an example of how independent researchers can collaborate with responsible corporations to locate and fix dangerous security vulnerabilities.
Despite these efforts, cybersecurity experts remain vigilant. Attacks that exploit vulnerabilities such as CVE-2025-33053 are growing in complexity and frequency. Given heightened threats organizations need to move quickly and with a broad stroke to harden their security.
Despite these efforts, cybersecurity experts remain vigilant. The frequency and sophistication of attacks exploiting vulnerabilities like CVE-2025-33053 indicate a pressing need for organizations to adopt comprehensive security measures.
“Over the past several months, the CLFS driver has become a consistent focus for both threat actors and security researchers due to its exploitation in multiple ransomware operations.” – Ben McCarthy, lead cyber security engineer at Immersive