Microsoft’s monthly Patch Tuesday always draws focused attention from IT professionals, cybersecurity experts, and everyday users alike, but the stakes for June 2025 are higher than usual. This month, Microsoft released security updates to remediate at least 67 vulnerabilities across its Windows ecosystem, including Windows operating systems and core software components. While applying updates is a routine part of IT hygiene, several factors make the June 2025 patch cycle particularly noteworthy and deserving of close critical scrutiny.
Patch Tuesday, Microsoft’s tradition of monthly cumulative security fixes, once again highlights the company’s ongoing struggle to keep pace with emerging threats and the sheer complexity of its own software stack. This month, the focal point is a remote code execution (RCE) vulnerability under active exploitation—CVE-2025-33053—in the Windows implementation of WebDAV, as well as a dangerous “elevation of privilege” flaw in the Windows Server Message Block (SMB) client, identified as CVE-2025-33073.
Adam Barnett, lead software engineer at Rapid7, points out a critical nuance often overlooked: Microsoft’s official advisory fails to mention that Windows’ WebDAV/WebClient has been deprecated since November 2023. In practice, this means that unless a user has deliberately enabled the WebClient service, systems should be resistant to remote exploitation. Still, Microsoft patched all supported Windows versions, including those released after the deprecation, such as Server 2025 and Windows 11 24H2, out of an abundance of caution.
The patch’s criticality is further underscored by its low attack complexity. Exploitation requires nothing more than a user clicking a malicious link, with no special configuration or preparation needed. While Microsoft asserts that exposure is limited if the WebClient is not enabled, environments relying on legacy infrastructure are at concrete risk—attackers need only identify and target these deployments.
Proof-of-concept exploit code for CVE-2025-33073 is now publicly available, amplifying the urgency for rapid patch deployment. The flaw’s Common Vulnerability Scoring System (CVSS) score is 8.8 out of 10, categorizing it as a high-risk issue.
Alex Vovk, co-founder and CEO of Action1, offers blunt assessment: “What makes this especially dangerous is that no further user interaction is required after the initial connection—something attackers can often trigger without the user realizing it.” Once a user connects to a malicious SMB resource—often a seamless step in daily network use—attacker code can run automatically under the SYSTEM account.
Tenable’s Satnam Narang warns organizations that, despite no current patch, immediate steps can help mitigate risks: review and constrain Active Directory permissions, especially for principals, to limit potential abuse vectors until an official fix is issued.
Microsoft’s advisory confirms the deprecation of WebClient and, as noted by industry experts, still issues patches for new Windows releases post-deprecation, demonstrating caution and a clear understanding of long-tail risk in enterprise deployments.
No evidence contradicts the published patch counts and affected software listings, but users and IT departments should confirm with Microsoft’s official Patch Tuesday roundups from resources such as the SANS Internet Storm Center and Action1’s detailed advisories.
For home users, the patching process is more automated than ever, but the combination of third-party browser and Adobe updates alongside Windows patches can create daunting update fatigue. The message remains: do not neglect browser and document readers, as threat actors frequently chain vulnerabilities across multiple vendor products for maximum effect.
The continued prevalence of zero-day attacks on mainstream platforms—Windows, Chrome, Acrobat Reader—underscores the critical need for robust patch management and vendor diversity across the enterprise IT landscape. Organizations that delay patching or lack comprehensive visibility into their infrastructure remain tantalizingly easy prey for both opportunistic and persistent attackers.
End-users, for their part, should not ignore update notifications, especially for popular browsers and productivity tools. Cybercriminals are increasingly quick to weaponize browser-based vulnerabilities, and chained exploits targeting both operating systems and widely installed applications are on the rise.
The evolving security landscape makes June 2025’s Patch Tuesday a pivotal case study: it reveals not only the ceaseless innovation of cyber attackers, but also the imperative for defenders to embrace both technological upgrades and organizational vigilance. By focusing on timely security updates, disabling unnecessary legacy features, and maintaining a layered approach to access control, IT professionals can turn the lessons of this cycle into enhanced resilience for Windows environments, now and into the uncertain future.
Source: Krebs on Security Patch Tuesday, June 2025 Edition – Krebs on Security
A Closer Look at the June 2025 Patch Tuesday Vulnerabilities
Patch Tuesday, Microsoft’s tradition of monthly cumulative security fixes, once again highlights the company’s ongoing struggle to keep pace with emerging threats and the sheer complexity of its own software stack. This month, the focal point is a remote code execution (RCE) vulnerability under active exploitation—CVE-2025-33053—in the Windows implementation of WebDAV, as well as a dangerous “elevation of privilege” flaw in the Windows Server Message Block (SMB) client, identified as CVE-2025-33073.CVE-2025-33053: The WebDAV Remote Code Execution Risk
Technical Overview
CVE-2025-33053 affects Microsoft’s implementation of WebDAV, an extension of the HTTP protocol that enables users to remotely manage content on web servers. Notably, exploitation of this bug allows malicious actors to execute arbitrary code remotely—a high-value attack vector, especially in enterprise and legacy deployments.Legacy Risks and Real-World Impact
Although contemporary Windows installations do not enable WebDAV (specifically the WebClient service) by default, its entrenchment in many specialized industrial environments and legacy setups amplifies its relevance. As Seth Hoyt, senior security engineer at Automox, notes, WebDAV’s presence in older configurations or unique deployments ensures that a meaningful subset of systems remains vulnerable.Adam Barnett, lead software engineer at Rapid7, points out a critical nuance often overlooked: Microsoft’s official advisory fails to mention that Windows’ WebDAV/WebClient has been deprecated since November 2023. In practice, this means that unless a user has deliberately enabled the WebClient service, systems should be resistant to remote exploitation. Still, Microsoft patched all supported Windows versions, including those released after the deprecation, such as Server 2025 and Windows 11 24H2, out of an abundance of caution.
The patch’s criticality is further underscored by its low attack complexity. Exploitation requires nothing more than a user clicking a malicious link, with no special configuration or preparation needed. While Microsoft asserts that exposure is limited if the WebClient is not enabled, environments relying on legacy infrastructure are at concrete risk—attackers need only identify and target these deployments.
Assessment and Mitigation
Given active exploitation in the wild and the simplicity of triggering the vulnerability, organizations should treat this as a priority fix, especially for systems where the WebClient service may be running. Security teams are urged to audit their environments, ensure WebDAV components are disabled if unnecessary, and apply the update promptly.CVE-2025-33073: Elevation of Privilege in SMB Client
Core Details
The impact of CVE-2025-33073 is severe. This vulnerability resides in the Windows SMB client, a critical service underpinning file, printer sharing, and inter-process communication in nearly every Windows deployment—personal, enterprise, and cloud-based alike. Successful exploitation grants attackers SYSTEM-level privileges, the highest level of authority on a Windows machine.Proof-of-concept exploit code for CVE-2025-33073 is now publicly available, amplifying the urgency for rapid patch deployment. The flaw’s Common Vulnerability Scoring System (CVSS) score is 8.8 out of 10, categorizing it as a high-risk issue.
Alex Vovk, co-founder and CEO of Action1, offers blunt assessment: “What makes this especially dangerous is that no further user interaction is required after the initial connection—something attackers can often trigger without the user realizing it.” Once a user connects to a malicious SMB resource—often a seamless step in daily network use—attacker code can run automatically under the SYSTEM account.
Scope and Exposure
The ubiquity of SMB, and its integration in Active Directory, file sharing, and cross-platform operations, means a very broad footprint for possible attack. Even fully patched, modern machines could be at risk if patches are not applied immediately.Recommended Countermeasures
Immediate patching is mandatory for all environments. As SMB is so deeply tied to core Windows networking, vulnerabilities in this component represent foundational weaknesses. Until fully patched, organizations should strongly consider restricting outbound SMB connections where possible and monitoring network traffic for suspicious SMB activity.What’s Missing? The “BadSuccessor” Bug in Server 2025
A notable absence from this month’s Patch Tuesday batch is a fix for the newly-discovered “BadSuccessor” vulnerability, which affects Windows Server 2025 domain controllers. This bug, revealed by Akamai researchers in May, allows attackers to assume the privileges of any user in Active Directory under specific conditions. The presence of public proof-of-concept exploits further raises concern.Tenable’s Satnam Narang warns organizations that, despite no current patch, immediate steps can help mitigate risks: review and constrain Active Directory permissions, especially for principals, to limit potential abuse vectors until an official fix is issued.
Broad Patch Landscape: Ten Critical Fixes, Browser Updates, and Third-Party Risks
Critical Flaws Addressed
Of the 67 vulnerabilities addressed this month, Microsoft rated 10 as “critical.” Eight of these critical issues impact remote code execution, always the most prized class of bugs for attackers because they allow for arbitrary, often automated, exploitation over network boundaries. While Microsoft has not detailed every critical bug, the across-the-board risk level implies attentive prioritization for both Windows desktops and servers.Browser Security: Chrome and Firefox
In a high-stakes digital landscape, browsers represent a frequent attack vector. This month, Google and Mozilla separately issued emergency updates: Chrome’s latest patch cycle closes two zero-day vulnerabilities, CVE-2025-5419 and CVE-2025-4664, both under active attack in the wild. Firefox also rolled out security updates that require users to restart the browser for changes to take full effect. These releases follow an ongoing trend: browser vendors must deploy rapid out-of-band updates to counteract nimble adversaries weaponizing previously unpublished flaws.Adobe’s Massive Patch Cycle
Adobe, often a staple of enterprise document and media workflows, released patches for Acrobat Reader and six further products, addressing a staggering 259 vulnerabilities—most concentrated in Experience Manager. This volume, although not unprecedented for Adobe, reflects both the complexity of its product suite and its historical attractiveness as a target for attackers seeking productive beachheads in business environments.Verification and Critical Analysis of Vendor Claims
On the WebDAV and SMB Flaws
Independent security researchers and industry advisories corroborate the technical details and severity of both CVE-2025-33053 and CVE-2025-33073. Neither issue is theoretical: there are clear reports of exploitation, proof-of-concept code is readily found in public repositories, and Microsoft’s advisories confirm exploitation for the WebDAV flaw and publicly available exploit samples for the SMB bug.Microsoft’s advisory confirms the deprecation of WebClient and, as noted by industry experts, still issues patches for new Windows releases post-deprecation, demonstrating caution and a clear understanding of long-tail risk in enterprise deployments.
Gaps and Open Questions
The omission of a fix for the “BadSuccessor” vulnerability is not unusual for complex zero-day disclosures, but organizations should be aware of the risk that attackers will “move fast” to weaponize public research. History suggests attackers swiftly adapt proofs-of-concept, making temporary workarounds essential.No evidence contradicts the published patch counts and affected software listings, but users and IT departments should confirm with Microsoft’s official Patch Tuesday roundups from resources such as the SANS Internet Storm Center and Action1’s detailed advisories.
Broader Implications for Enterprise and End Users
The Challenge of Speed and Scale
Each Patch Tuesday, but especially notable cycles like June 2025, raises the perennial challenge for security teams: balancing the need for rapid remediation with the attendant risks of large-scale deployments. Even well-tested patches can sometimes lead to unintended side effects, application incompatibilities, or unplanned downtime for mission-critical systems.For home users, the patching process is more automated than ever, but the combination of third-party browser and Adobe updates alongside Windows patches can create daunting update fatigue. The message remains: do not neglect browser and document readers, as threat actors frequently chain vulnerabilities across multiple vendor products for maximum effect.
The Risk of Legacy Systems
The WebDAV story is a vivid reminder of the hazards posed by legacy components and “zombie” features that linger in enterprise setups. While deprecation is a positive step, real-world inertia means unneeded services often remain enabled long after their official retirement. Proactive system audit and hardening, especially disabling unused legacy services, must be part of enterprise defense-in-depth strategies.The Expansion of Public Proof-of-Concepts
The ready availability of public exploit scripts for both the SMB and Active Directory bugs fundamentally changes the risk calculus for defenders. Script kiddies and sophisticated adversaries alike can quickly leverage these tools, shrinking the time window for safe patching and increasing the likelihood of opportunistic exploitation.Practical Guidance: What to Do Now
A few recommendations emerge clearly from this month’s security patch landscape:- Prioritize patches for CVE-2025-33053 (WebDAV) and CVE-2025-33073 (SMB client), especially for systems where exposure is likely or critical business functions depend on these components.
- Review and limit Active Directory permissions on any environments running Windows Server 2025, particularly domain controllers, as a stopgap against exploitation of the “BadSuccessor” flaw.
- Apply browser updates for both Google Chrome and Mozilla Firefox immediately. Restart browsers to ensure patches are active.
- Patch Adobe products, most notably Acrobat Reader and any instances of Adobe Experience Manager, focusing on environments where document workflow is tightly integrated with business processes.
- Audit legacy services: Disable WebClient (WebDAV) and other deprecated Windows features unless absolutely necessary.
- Monitor vendor advisories and community resources for emerging issues, potential patch problems, and mitigation techniques as new details surface.
Critical Reflections and SEO-Focused Conclusions
June 2025’s Patch Tuesday demonstrates both the strengths and perennial weaknesses of modern software maintenance practices. Microsoft’s comprehensive update cadence, broad support for legacy and new systems, and rapid patch deployment for actively exploited threats are praiseworthy. However, the continuing presence of powerful, easily exploitable vulnerabilities in foundational system components like SMB and WebDAV—years after their first use—speaks to the intractable problem of code complexity and technical debt within Windows.The continued prevalence of zero-day attacks on mainstream platforms—Windows, Chrome, Acrobat Reader—underscores the critical need for robust patch management and vendor diversity across the enterprise IT landscape. Organizations that delay patching or lack comprehensive visibility into their infrastructure remain tantalizingly easy prey for both opportunistic and persistent attackers.
End-users, for their part, should not ignore update notifications, especially for popular browsers and productivity tools. Cybercriminals are increasingly quick to weaponize browser-based vulnerabilities, and chained exploits targeting both operating systems and widely installed applications are on the rise.
The evolving security landscape makes June 2025’s Patch Tuesday a pivotal case study: it reveals not only the ceaseless innovation of cyber attackers, but also the imperative for defenders to embrace both technological upgrades and organizational vigilance. By focusing on timely security updates, disabling unnecessary legacy features, and maintaining a layered approach to access control, IT professionals can turn the lessons of this cycle into enhanced resilience for Windows environments, now and into the uncertain future.
Source: Krebs on Security Patch Tuesday, June 2025 Edition – Krebs on Security
