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Microsoft Patch Tuesday, September 2025 Edition

9 September 2025 at 17:21

Microsoft Corp. today issued security updates to fix more than 80 vulnerabilities in its Windows operating systems and software. There are no known “zero-day” or actively exploited vulnerabilities in this month’s bundle from Redmond, which nevertheless includes patches for 13 flaws that earned Microsoft’s most-dire “critical” label. Meanwhile, both Apple and Google recently released updates to fix zero-day bugs in their devices.

Microsoft assigns security flaws a “critical” rating when malware or miscreants can exploit them to gain remote access to a Windows system with little or no help from users. Among the more concerning critical bugs quashed this month is CVE-2025-54918. The problem here resides with Windows NTLM, or NT LAN Manager, a suite of code for managing authentication in a Windows network environment.

Redmond rates this flaw as “Exploitation More Likely,” and although it is listed as a privilege escalation vulnerability, Kev Breen at Immersive says this one is actually exploitable over the network or the Internet.

“From Microsoft’s limited description, it appears that if an attacker is able to send specially crafted packets over the network to the target device, they would have the ability to gain SYSTEM-level privileges on the target machine,” Breen said. “The patch notes for this vulnerability state that ‘Improper authentication in Windows NTLM allows an authorized attacker to elevate privileges over a network,’ suggesting an attacker may already need to have access to the NTLM hash or the user’s credentials.”

Breen said another patch — CVE-2025-55234, a 8.8 CVSS-scored flaw affecting the Windows SMB client for sharing files across a network — also is listed as privilege escalation bug but is likewise remotely exploitable. This vulnerability was publicly disclosed prior to this month.

“Microsoft says that an attacker with network access would be able to perform a replay attack against a target host, which could result in the attacker gaining additional privileges, which could lead to code execution,” Breen noted.

CVE-2025-54916 is an “important” vulnerability in Windows NTFS — the default filesystem for all modern versions of Windows — that can lead to remote code execution. Microsoft likewise thinks we are more than likely to see exploitation of this bug soon: The last time Microsoft patched an NTFS bug was in March 2025 and it was already being exploited in the wild as a zero-day.

“While the title of the CVE says ‘Remote Code Execution,’ this exploit is not remotely exploitable over the network, but instead needs an attacker to either have the ability to run code on the host or to convince a user to run a file that would trigger the exploit,” Breen said. “This is commonly seen in social engineering attacks, where they send the user a file to open as an attachment or a link to a file to download and run.”

Critical and remote code execution bugs tend to steal all the limelight, but Tenable Senior Staff Research Engineer Satnam Narang notes that nearly half of all vulnerabilities fixed by Microsoft this month are privilege escalation flaws that require an attacker to have gained access to a target system first before attempting to elevate privileges.

“For the third time this year, Microsoft patched more elevation of privilege vulnerabilities than remote code execution flaws,” Narang observed.

On Sept. 3, Google fixed two flaws that were detected as exploited in zero-day attacks, including CVE-2025-38352, an elevation of privilege in the Android kernel, and CVE-2025-48543, also an elevation of privilege problem in the Android Runtime component.

Also, Apple recently patched its seventh zero-day (CVE-2025-43300) of this year. It was part of an exploit chain used along with a vulnerability in the WhatsApp (CVE-2025-55177) instant messenger to hack Apple devices. Amnesty International reports that the two zero-days have been used in “an advanced spyware campaign” over the past 90 days. The issue is fixed in iOS 18.6.2, iPadOS 18.6.2, iPadOS 17.7.10, macOS Sequoia 15.6.1, macOS Sonoma 14.7.8, and macOS Ventura 13.7.8.

The SANS Internet Storm Center has a clickable breakdown of each individual fix from Microsoft, indexed by severity and CVSS score. Enterprise Windows admins involved in testing patches before rolling them out should keep an eye on askwoody.com, which often has the skinny on wonky updates.

AskWoody also reminds us that we’re now just two months out from Microsoft discontinuing free security updates for Windows 10 computers. For those interested in safely extending the lifespan and usefulness of these older machines, check out last month’s Patch Tuesday coverage for a few pointers.

As ever, please don’t neglect to back up your data (if not your entire system) at regular intervals, and feel free to sound off in the comments if you experience problems installing any of these fixes.

Microsoft Patch Tuesday, August 2025 Edition

12 August 2025 at 18:14

Microsoft today released updates to fix more than 100 security flaws in its Windows operating systems and other software. At least 13 of the bugs received Microsoft’s most-dire “critical” rating, meaning they could be abused by malware or malcontents to gain remote access to a Windows system with little or no help from users.

August’s patch batch from Redmond includes an update for CVE-2025-53786, a vulnerability that allows an attacker to pivot from a compromised Microsoft Exchange Server directly into an organization’s cloud environment, potentially gaining control over Exchange Online and other connected Microsoft Office 365 services. Microsoft first warned about this bug on Aug. 6, saying it affects Exchange Server 2016 and Exchange Server 2019, as well as its flagship Exchange Server Subscription Edition.

Ben McCarthy, lead cyber security engineer at Immersive, said a rough search reveals approximately 29,000 Exchange servers publicly facing on the internet that are vulnerable to this issue, with many of them likely to have even older vulnerabilities.

McCarthy said the fix for CVE-2025-53786 requires more than just installing a patch, such as following Microsoft’s manual instructions for creating a dedicated service to oversee and lock down the hybrid connection.

“In effect, this vulnerability turns a significant on-premise Exchange breach into a full-blown, difficult-to-detect cloud compromise with effectively living off the land techniques which are always harder to detect for defensive teams,” McCarthy said.

CVE-2025-53779 is a weakness in the Windows Kerberos authentication system that allows an unauthenticated attacker to gain domain administrator privileges. Microsoft credits the discovery of the flaw to Akamai researcher Yuval Gordon, who dubbed it “BadSuccessor” in a May 2025 blog post. The attack exploits a weakness in “delegated Managed Service Account” or dMSA — a feature that was introduced in Windows Server 2025.

Some of the critical flaws addressed this month with the highest severity (between 9.0 and 9.9 CVSS scores) include a remote code execution bug in the Windows GDI+ component that handles graphics rendering (CVE-2025-53766) and CVE-2025-50165, another graphics rendering weakness. Another critical patch involves CVE-2025-53733, a vulnerability in Microsoft Word that can be exploited without user interaction and triggered through the Preview Pane.

One final critical bug tackled this month deserves attention: CVE-2025-53778, a bug in Windows NTLM, a core function of how Windows systems handle network authentication. According to Microsoft, the flaw could allow an attacker with low-level network access and basic user privileges to exploit NTLM and elevate to SYSTEM-level access — the highest level of privilege in Windows. Microsoft rates the exploitation of this bug as “more likely,” although there is no evidence the vulnerability is being exploited at the moment.

Feel free to holler in the comments if you experience problems installing any of these updates. As ever, the SANS Internet Storm Center has its useful breakdown of the Microsoft patches indexed by severity and CVSS score, and AskWoody.com is keeping an eye out for Windows patches that may cause problems for enterprises and end users.

GOOD MIGRATIONS

Windows 10 users out there likely have noticed by now that Microsoft really wants you to upgrade to Windows 11. The reason is that after the Patch Tuesday on October 14, 2025, Microsoft will stop shipping free security updates for Windows 10 computers. The trouble is, many PCs running Windows 10 do not meet the hardware specifications required to install Windows 11 (or they do, but just barely).

If the experience with Windows XP is any indicator, many of these older computers will wind up in landfills or else will be left running in an unpatched state. But if your Windows 10 PC doesn’t have the hardware chops to run Windows 11 and you’d still like to get some use out of it safely, consider installing a newbie-friendly version of Linux, like Linux Mint.

Like most modern Linux versions, Mint will run on anything with a 64-bit CPU that has at least 2GB of memory, although 4GB is recommended. In other words, it will run on almost any computer produced in the last decade.

There are many versions of Linux available, but Linux Mint is likely to be the most intuitive interface for regular Windows users, and it is largely configurable without any fuss at the text-only command-line prompt. Mint and other flavors of Linux come with LibreOffice, which is an open source suite of tools that includes applications similar to Microsoft Office, and it can open, edit and save documents as Microsoft Office files.

If you’d prefer to give Linux a test drive before installing it on a Windows PC, you can always just download it to a removable USB drive. From there, reboot the computer (with the removable drive plugged in) and select the option at startup to run the operating system from the external USB drive. If you don’t see an option for that after restarting, try restarting again and hitting the F8 button, which should open a list of bootable drives. Here’s a fairly thorough tutorial that walks through exactly how to do all this.

And if this is your first time trying out Linux, relax and have fun: The nice thing about a “live” version of Linux (as it’s called when the operating system is run from a removable drive such as a CD or a USB stick) is that none of your changes persist after a reboot. Even if you somehow manage to break something, a restart will return the system back to its original state.

Patch Tuesday, June 2025 Edition

10 June 2025 at 20:10

Microsoft today released security updates to fix at least 67 vulnerabilities in its Windows operating systems and software. Redmond warns that one of the flaws is already under active attack, and that software blueprints showing how to exploit a pervasive Windows bug patched this month are now public.

The sole zero-day flaw this month is CVE-2025-33053, a remote code execution flaw in the Windows implementation of WebDAV — an HTTP extension that lets users remotely manage files and directories on a server. While WebDAV isn’t enabled by default in Windows, its presence in legacy or specialized systems still makes it a relevant target, said Seth Hoyt, senior security engineer at Automox.

Adam Barnett, lead software engineer at Rapid7, said Microsoft’s advisory for CVE-2025-33053 does not mention that the Windows implementation of WebDAV is listed as deprecated since November 2023, which in practical terms means that the WebClient service no longer starts by default.

“The advisory also has attack complexity as low, which means that exploitation does not require preparation of the target environment in any way that is beyond the attacker’s control,” Barnett said. “Exploitation relies on the user clicking a malicious link. It’s not clear how an asset would be immediately vulnerable if the service isn’t running, but all versions of Windows receive a patch, including those released since the deprecation of WebClient, like Server 2025 and Windows 11 24H2.”

Microsoft warns that an “elevation of privilege” vulnerability in the Windows Server Message Block (SMB) client (CVE-2025-33073) is likely to be exploited, given that proof-of-concept code for this bug is now public. CVE-2025-33073 has a CVSS risk score of 8.8 (out of 10), and exploitation of the flaw leads to the attacker gaining “SYSTEM” level control over a vulnerable PC.

“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,” said Alex Vovk, co-founder and CEO of Action1. “Given the high privilege level and ease of exploitation, this flaw poses a significant risk to Windows environments. The scope of affected systems is extensive, as SMB is a core Windows protocol used for file and printer sharing and inter-process communication.”

Beyond these highlights, 10 of the vulnerabilities fixed this month were rated “critical” by Microsoft, including eight remote code execution flaws.

Notably absent from this month’s patch batch is a fix for a newly discovered weakness in Windows Server 2025 that allows attackers to act with the privileges of any user in Active Directory. The bug, dubbed “BadSuccessor,” was publicly disclosed by researchers at Akamai on May 21, and several public proof-of-concepts are now available. Tenable’s Satnam Narang said organizations that have at least one Windows Server 2025 domain controller should review permissions for principals and limit those permissions as much as possible.

Adobe has released updates for Acrobat Reader and six other products addressing at least 259 vulnerabilities, most of them in an update for Experience Manager. Mozilla Firefox and Google Chrome both recently released security updates that require a restart of the browser to take effect. The latest Chrome update fixes two zero-day exploits in the browser (CVE-2025-5419 and CVE-2025-4664).

For a detailed breakdown on the individual security updates released by Microsoft today, check out the Patch Tuesday roundup from the SANS Internet Storm Center. Action 1 has a breakdown of patches from Microsoft and a raft of other software vendors releasing fixes this month. As always, please back up your system and/or data before patching, and feel free to drop a note in the comments if you run into any problems applying these updates.

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