Microsoft: Happy 2025. Here’s 161 Security Updates

Microsoft today unleashed updates to plug a whopping 161 security vulnerabilities in Windows and related software, including three “zero-day” weaknesses that are already under active attack. Redmond’s inaugural Patch Tuesday of 2025 bundles more fixes than the company has shipped in one go since 2017.

Rapid7‘s Adam Barnett says January marks the fourth consecutive month where Microsoft has published zero-day vulnerabilities on Patch Tuesday without evaluating any of them as critical severity at time of publication. Today also saw the publication of nine critical remote code execution (RCE) vulnerabilities.

The Microsoft flaws already seeing active attacks include CVE-2025-21333, CVE-2025-21334 and, you guessed it– CVE-2025-21335. These are sequential because all reside in Windows Hyper-V, a component that is heavily embedded in modern Windows 11 operating systems and used for security features including device guard and credential guard.

Tenable’s Satnam Narang says little is known about the in-the-wild exploitation of these flaws, apart from the fact that they are all “privilege escalation” vulnerabilities. Narang said we tend to see a lot of elevation of privilege bugs exploited in the wild as zero-days in Patch Tuesday because it’s not always initial access to a system that’s a challenge for attackers as they have various avenues in their pursuit.

“As elevation of privilege bugs, they’re being used as part of post-compromise activity, where an attacker has already accessed a target system,” he said. “It’s kind of like if an attacker is able to enter a secure building, they’re unable to access more secure parts of the facility because they have to prove that they have clearance. In this case, they’re able to trick the system into believing they should have clearance.”

Several bugs addressed today earned CVSS (threat rating) scores of 9.8 out of a possible 10, including CVE-2025-21298, a weakness in Windows that could allow attackers to run arbitrary code by getting a target to open a malicious .rtf file, documents typically opened on Office applications like Microsoft Word. Microsoft has rated this flaw “exploitation more likely.”

Ben Hopkins at Immersive Labs called attention to the CVE-2025-21311, a 9.8 “critical” bug in Windows NTLMv1 (NT LAN Manager version 1), an older Microsoft authentication protocol that is still used by many organizations.

“What makes this vulnerability so impactful is the fact that it is remotely exploitable, so attackers can reach the compromised machine(s) over the internet, and the attacker does not need significant knowledge or skills to achieve repeatable success with the same payload across any vulnerable component,” Hopkins wrote.

Kev Breen at Immersive points to an interesting flaw (CVE-2025-21210) that Microsoft fixed in its full disk encryption suite Bitlocker that the software giant has dubbed “exploitation more likely.” Specifically, this bug holds out the possibility that in some situations the hibernation image created when one closes the laptop lid on an open Windows session may not be fully encrypted and could be recovered in plain text.

“Hibernation images are used when a laptop goes to sleep and contains the contents that were stored in RAM at the moment the device powered down,” Breen noted. “This presents a significant potential impact as RAM can contain sensitive data (such as passwords, credentials and PII) that may have been in open documents or browser sessions and can all be recovered with free tools from hibernation files.”

Tenable’s Narang also highlighted a trio of vulnerabilities in Microsoft Access fixed this month and credited to Unpatched.ai, a security research effort that is aided by artificial intelligence looking for vulnerabilities in code. Tracked as CVE-2025-21186, CVE-2025-21366, and CVE-2025-21395, these are remote code execution bugs that are exploitable if an attacker convinces a target to download and run a malicious file through social engineering. Unpatched.ai was also credited with discovering a flaw in the December 2024 Patch Tuesday release (CVE-2024-49142).

“Automated vulnerability detection using AI has garnered a lot of attention recently, so it’s noteworthy to see this service being credited with finding bugs in Microsoft products,” Narang observed. “It may be the first of many in 2025.”

If you’re a Windows user who has automatic updates turned off and haven’t updated in a while, it’s probably time to play catch up. Please consider backing up important files and/or the entire hard drive before updating. And if you run into any problems installing this month’s patch batch, drop a line in the comments below, please.

Further reading on today’s patches from Microsoft:

Tenable blog

SANS Internet Storm Center

Ask Woody

The End of an Era: Microsoft Phases Out VBScript for JavaScript and PowerShell

Microsoft on Wednesday outlined its plans to deprecate Visual Basic Script (VBScript) in the second half of 2024 in favor of more advanced alternatives such as JavaScript and PowerShell. "Technology has advanced over the years, giving rise to more powerful and versatile scripting languages such as JavaScript and PowerShell," Microsoft Program Manager Naveen Shankar said. "These languages

Critical Veeam Backup Enterprise Manager Flaw Allows Authentication Bypass

Users of Veeam Backup Enterprise Manager are being urged to update to the latest version following the discovery of a critical security flaw that could permit an adversary to bypass authentication protections. Tracked as CVE-2024-29849 (CVSS score: 9.8), the vulnerability could allow an unauthenticated attacker to log in to the Veeam Backup Enterprise Manager web interface as

APT28 Hacker Group Targeting Europe, Americas, Asia in Widespread Phishing Scheme

The Russia-linked threat actor known as APT28 has been linked to multiple ongoing phishing campaigns that employ lure documents imitating government and non-governmental organizations (NGOs) in Europe, the South Caucasus, Central Asia, and North and South America. "The uncovered lures include a mixture of internal and publicly available documents, as well as possible actor-generated

Critical Exchange Server Flaw (CVE-2024-21410) Under Active Exploitation

Microsoft on Wednesday acknowledged that a newly disclosed critical security flaw in Exchange Server has been actively exploited in the wild, a day after it released fixes for the vulnerability as part of its Patch Tuesday updates. Tracked as CVE-2024-21410 (CVSS score: 9.8), the issue has been described as a case of privilege escalation impacting the Exchange Server. "An attacker

Russian APT28 Hackers Targeting High-Value Orgs with NTLM Relay Attacks

Russian state-sponsored actors have staged NT LAN Manager (NTLM) v2 hash relay attacks through various methods from April 2022 to November 2023, targeting high-value targets worldwide. The attacks, attributed to an "aggressive" hacking crew called APT28, have set their eyes on organizations dealing with foreign affairs, energy, defense, and transportation, as well as those involved with

Researchers Uncover How Outlook Vulnerability Could Leak Your NTLM Passwords

A now-patched security flaw in Microsoft Outlook could be exploited by threat actors to access NT LAN Manager (NTLM) v2 hashed passwords when opening a specially crafted file. The issue, tracked as CVE-2023-35636 (CVSS score: 6.5), was addressed by the tech giant as part of its Patch Tuesday updates for December 2023. "In an email attack scenario, an attacker could exploit the

Alert: New Vulnerabilities Discovered in QNAP and Kyocera Device Manager

A security flaw has been disclosed in Kyocera’s Device Manager product that could be exploited by bad actors to carry out malicious activities on affected systems. "This vulnerability allows attackers to coerce authentication attempts to their own resources, such as a malicious SMB share, to capture or relay Active Directory hashed credentials if the ‘Restrict NTLM: Outgoing NTLM

Beware: Experts Reveal New Details on Zero-Click Outlook RCE Exploits

Technical details have emerged about two now-patched security flaws in Microsoft Windows that could be chained by threat actors to achieve remote code execution on the Outlook email service sans any user interaction. "An attacker on the internet can chain the vulnerabilities together to create a full, zero-click remote code execution (RCE) exploit against Outlook clients," Akamai security

Microsoft to Phase Out NTLM in Favor of Kerberos for Stronger Authentication

Microsoft has announced that it plans to eliminate NT LAN Manager (NTLM) in Windows 11 in the future, as it pivots to alternative methods for authentication and bolster security. "The focus is on strengthening the Kerberos authentication protocol, which has been the default since 2000, and reducing reliance on NT LAN Manager (NTLM)," the tech giant said. "New features for Windows 11 include

Cybercriminals Using PowerShell to Steal NTLMv2 Hashes from Compromised Windows

A new cyber attack campaign is leveraging the PowerShell script associated with a legitimate red teaming tool to plunder NTLMv2 hashes from compromised Windows systems primarily located in Australia, Poland, and Belgium. The activity has been codenamed Steal-It by Zscaler ThreatLabz. "In this campaign, the threat actors steal and exfiltrate NTLMv2 hashes using customized versions of Nishang's 

Microsoft Warns of Stealthy Outlook Vulnerability Exploited by Russian Hackers

Microsoft on Friday shared guidance to help customers discover indicators of compromise (IoCs) associated with a recently patched Outlook vulnerability. Tracked as CVE-2023-23397 (CVSS score: 9.8), the critical flaw relates to a case of privilege escalation that could be exploited to steal NT Lan Manager (NTLM) hashes and stage a relay attack without requiring any user interaction. "External

Microsoft fixes two 0-days on Patch Tuesday – update now!

An email you haven't even looked at yet could be used to trick Outlook into helping crooks to logon as you.