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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.
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.
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.
Microsoft today issued security updates to fix at least 56 vulnerabilities in its Windows operating systems and supported software, including two zero-day flaws that are being actively exploited.
All supported Windows operating systems will receive an update this month for a buffer overflow vulnerability that carries the catchy name CVE-2025-21418. This patch should be a priority for enterprises, as Microsoft says it is being exploited, has low attack complexity, and no requirements for user interaction.
Tenable senior staff research engineer Satnam Narang noted that since 2022, there have been nine elevation of privilege vulnerabilities in this same Windows component — three each year — including one in 2024 that was exploited in the wild as a zero day (CVE-2024-38193).
“CVE-2024-38193 was exploited by the North Korean APT group known as Lazarus Group to implant a new version of the FudModule rootkit in order to maintain persistence and stealth on compromised systems,” Narang said. “At this time, it is unclear if CVE-2025-21418 was also exploited by Lazarus Group.”
The other zero-day, CVE-2025-21391, is an elevation of privilege vulnerability in Windows Storage that could be used to delete files on a targeted system. Microsoft’s advisory on this bug references something called “CWE-59: Improper Link Resolution Before File Access,” says no user interaction is required, and that the attack complexity is low.
Adam Barnett, lead software engineer at Rapid7, said although the advisory provides scant detail, and even offers some vague reassurance that ‘an attacker would only be able to delete targeted files on a system,’ it would be a mistake to assume that the impact of deleting arbitrary files would be limited to data loss or denial of service.
“As long ago as 2022, ZDI researchers set out how a motivated attacker could parlay arbitrary file deletion into full SYSTEM access using techniques which also involve creative misuse of symbolic links,”Barnett wrote.
One vulnerability patched today that was publicly disclosed earlier is CVE-2025-21377, another weakness that could allow an attacker to elevate their privileges on a vulnerable Windows system. Specifically, this is yet another Windows flaw that can be used to steal NTLMv2 hashes — essentially allowing an attacker to authenticate as the targeted user without having to log in.
According to Microsoft, minimal user interaction with a malicious file is needed to exploit CVE-2025-21377, including selecting, inspecting or “performing an action other than opening or executing the file.”
“This trademark linguistic ducking and weaving may be Microsoft’s way of saying ‘if we told you any more, we’d give the game away,'” Barnett said. “Accordingly, Microsoft assesses exploitation as more likely.”
The SANS Internet Storm Center has a handy list of all the Microsoft patches released today, indexed by severity. Windows enterprise administrators would do well to keep an eye on askwoody.com, which often has the scoop on any patches causing problems.
It’s getting harder to buy Windows software that isn’t also bundled with Microsoft’s flagship Copilot artificial intelligence (AI) feature. Last month Microsoft started bundling Copilot with Microsoft Office 365, which Redmond has since rebranded as “Microsoft 365 Copilot.” Ostensibly to offset the costs of its substantial AI investments, Microsoft also jacked up prices from 22 percent to 30 percent for upcoming license renewals and new subscribers.
Office-watch.com writes that existing Office 365 users who are paying an annual cloud license do have the option of “Microsoft 365 Classic,” an AI-free subscription at a lower price, but that many customers are not offered the option until they attempt to cancel their existing Office subscription.
In other security patch news, Apple has shipped iOS 18.3.1, which fixes a zero day vulnerability (CVE-2025-24200) that is showing up in attacks.
Adobe has issued security updates that fix a total of 45 vulnerabilities across InDesign, Commerce, Substance 3D Stager, InCopy, Illustrator, Substance 3D Designer and Photoshop Elements.
Chris Goettl at Ivanti notes that Google Chrome is shipping an update today which will trigger updates for Chromium based browsers including Microsoft Edge, so be on the lookout for Chrome and Edge updates as we proceed through the week.
Microsoft Corp. today issued software updates to plug at least 139 security holes in various flavors of Windows and other Microsoft products. Redmond says attackers are already exploiting at least two of the vulnerabilities in active attacks against Windows users.
The first Microsoft zero-day this month is CVE-2024-38080, a bug in the Windows Hyper-V component that affects Windows 11 and Windows Server 2022 systems. CVE-2024-38080 allows an attacker to increase their account privileges on a Windows machine. Although Microsoft says this flaw is being exploited, it has offered scant details about its exploitation.
The other zero-day is CVE-2024-38112, which is a weakness in MSHTML, the proprietary engine of Microsoft’s Internet Explorer web browser. Kevin Breen, senior director of threat research at Immersive Labs, said exploitation of CVE-2024-38112 likely requires the use of an “attack chain” of exploits or programmatic changes on the target host, a la Microsoft’s description: “Successful exploitation of this vulnerability requires an attacker to take additional actions prior to exploitation to prepare the target environment.”
“Despite the lack of details given in the initial advisory, this vulnerability affects all hosts from Windows Server 2008 R2 onwards, including clients,” Breen said. “Due to active exploitation in the wild this one should be prioritized for patching.”
Satnam Narang, senior staff research engineer at Tenable, called special attention to CVE-2024-38021, a remote code execution flaw in Microsoft Office. Attacks on this weakness would lead to the disclosure of NTLM hashes, which could be leveraged as part of an NTLM relay or “pass the hash” attack, which lets an attacker masquerade as a legitimate user without ever having to log in.
“One of the more successful attack campaigns from 2023 used CVE-2023-23397, an elevation of privilege bug in Microsoft Outlook that could also leak NTLM hashes,” Narang said. “However, CVE-2024-38021 is limited by the fact that the Preview Pane is not an attack vector, which means that exploitation would not occur just by simply previewing the file.”
The security firm Morphisec, credited with reporting CVE-2024-38021 to Microsoft, said it respectfully disagrees with Microsoft’s “important” severity rating, arguing the Office flaw deserves a more dire “critical” rating given how easy it is for attackers to exploit.
“Their assessment differentiates between trusted and untrusted senders, noting that while the vulnerability is zero-click for trusted senders, it requires one click user interaction for untrusted senders,” Morphisec’s Michael Gorelik said in a blog post about their discovery. “This reassessment is crucial to reflect the true risk and ensure adequate attention and resources are allocated for mitigation.”
In last month’s Patch Tuesday, Microsoft fixed a flaw in its Windows WiFi driver that attackers could use to install malicious software just by sending a vulnerable Windows host a specially crafted data packet over a local network. Jason Kikta at Automox said this month’s CVE-2024-38053 — a security weakness in Windows Layer Two Bridge Network — is another local network “ping-of-death” vulnerability that should be a priority for road warriors to patch.
“This requires close access to a target,” Kikta said. “While that precludes a ransomware actor in Russia, it is something that is outside of most current threat models. This type of exploit works in places like shared office environments, hotels, convention centers, and anywhere else where unknown computers might be using the same physical link as you.”
Automox also highlighted three vulnerabilities in Windows Remote Desktop a service that allocates Client Access Licenses (CALs) when a client connects to a remote desktop host (CVE-2024-38077, CVE-2024-38074, and CVE-2024-38076). All three bugs have been assigned a CVSS score of 9.8 (out of 10) and indicate that a malicious packet could trigger the vulnerability.
Tyler Reguly at Fortra noted that today marks the End of Support date for SQL Server 2014, a platform that according to Shodan still has ~110,000 instances publicly available. On top of that, more than a quarter of all vulnerabilities Microsoft fixed this month are in SQL server.
“A lot of companies don’t update quickly, but this may leave them scrambling to update those environments to supported versions of MS-SQL,” Reguly said.
It’s a good idea for Windows end-users to stay current with security updates from Microsoft, which can quickly pile up otherwise. That doesn’t mean you have to install them on Patch Tuesday. Indeed, waiting a day or three before updating is a sane response, given that sometimes updates go awry and usually within a few days Microsoft has fixed any issues with its patches. It’s also smart to back up your data and/or image your Windows drive before applying new updates.
For a more detailed breakdown of the individual flaws addressed by Microsoft today, check out the SANS Internet Storm Center’s list. For those admins responsible for maintaining larger Windows environments, it often pays to keep an eye on Askwoody.com, which frequently points out when specific Microsoft updates are creating problems for a number of users.
As ever, if you experience any problems applying any of these updates, consider dropping a note about it in the comments; chances are decent someone else reading here has experienced the same issue, and maybe even has a solution.
Microsoft today released updates to fix more than five dozen security holes in its Windows operating systems and related software, including three “zero day” vulnerabilities that Microsoft warns are already being exploited in active attacks.
The zero-day threats targeting Microsoft this month include CVE-2023-36025, a weakness that allows malicious content to bypass the Windows SmartScreen Security feature. SmartScreen is a built-in Windows component that tries to detect and block malicious websites and files. Microsoft’s security advisory for this flaw says attackers could exploit it by getting a Windows user to click on a booby-trapped link to a shortcut file.
Kevin Breen, senior director of threat research at Immersive Labs, said emails with .url attachments or logs with processes spawning from .url files “should be a high priority for threat hunters given the active exploitation of this vulnerability in the wild.”
The second zero day this month is CVE-2023-36033, which is a vulnerability in the “DWM Core Library” in Microsoft Windows that was exploited in the wild as a zero day and publicly disclosed prior to patches being available. It affects Microsoft Windows 10 and later, as well as Microsoft Windows Server 2019 and subsequent versions.
“This vulnerability can be exploited locally, with low complexity and without needing high-level privileges or user interaction,” said Mike Walters, president and co-founder of the security firm Action1. “Attackers exploiting this flaw could gain SYSTEM privileges, making it an efficient method for escalating privileges, especially after initial access through methods like phishing.”
The final zero day in this month’s Patch Tuesday is a problem in the “Windows Cloud Files Mini Filter Driver” tracked as CVE-2023-36036 that affects Windows 10 and later, as well as Windows Server 2008 at later. Microsoft says it is relatively straightforward for attackers to exploit CVE-2023-36036 as a way to elevate their privileges on a compromised PC.
Beyond the zero day flaws, Breen said organizations running Microsoft Exchange Server should prioritize several new Exchange patches, including CVE-2023-36439, which is a bug that would allow attackers to install malicious software on an Exchange server. This weakness technically requires the attacker to be authenticated to the target’s local network, but Breen notes that a pair of phished Exchange credentials will provide that access nicely.
“This is typically achieved through social engineering attacks with spear phishing to gain initial access to a host before searching for other vulnerable internal targets – just because your Exchange Server doesn’t have internet-facing authentication doesn’t mean it’s protected,” Breen said.
Breen said this vulnerability goes hand in hand with three other Exchange bugs that Microsoft designated as “exploitation more likely:” CVE-2023-36050, CVE-2023-36039 and CVE-2023-36035.
Finally, the SANS Internet Storm Center points to two additional bugs patched by Microsoft this month that aren’t yet showing signs of active exploitation but that were made public prior to today and thus deserve prioritization. Those include: CVE-2023-36038, a denial of service vulnerability in ASP.NET Core, with a CVSS score of 8.2; and CVE-2023-36413: A Microsoft Office security feature bypass. Exploiting this vulnerability will bypass the protected mode when opening a file received via the web.
Windows users, please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any difficulties as a result of these patches.
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