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Ransomware developers are increasingly using intermittent encryption techniques that encrypt only portions of files rather than locking every byte, allowing attacks to complete faster while reducing the behavioral signals that many security tools rely on for detection. The approach is designed to preserve enough file corruption to disrupt operations while lowering CPU usage, shortening dwell time during encryption, and making malicious activity blend more easily with normal system behavior.
The shift highlights an ongoing evolution in crimeware tradecraft as ransomware operators refine methods to improve speed, stealth, and impact. By tuning how much of a file is encrypted and targeting data selectively, attackers can still render systems and business data unusable while complicating defensive monitoring and response, increasing pressure on organizations to detect ransomware earlier in the intrusion chain rather than relying solely on encryption-stage alerts.
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SentinelOne Labs published research describing a crimeware trend in which ransomware developers are adopting intermittent encryption techniques to reduce detection while still disrupting victims' data.
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Reporting and research published in mid-January 2026 highlights continued **high ransomware activity** and rapid evolution in initial-access and evasion tradecraft. A Symantec/Carbon Black Threat Hunter Team study cited by *Help Net Security* reports ransomware actors claimed **4,737 attacks in 2025**, with only brief slowdowns after major disruptions; the abrupt April 2025 shutdown of **RansomHub** was followed by affiliates quickly shifting to other operations, while **LockBit** failed to recover after late-2024 law-enforcement action. The same reporting notes a broader shift toward **extortion models that don’t rely on encryption**, emphasizing data theft and coercion as groups diversify pressure tactics. Multiple technical reports describe how attackers are improving delivery and resilience. *BleepingComputer* says **Gootloader** now uses heavily malformed ZIP files—concatenating **500–1,000** ZIP archives and manipulating ZIP structures (e.g., truncated `EOCD`)—to crash or defeat common analysis tools while still extracting via Windows’ default utility, supporting its role as an initial-access vector often preceding ransomware. *The Register* reports **DeadLock** ransomware uses **Polygon smart contracts** to frequently rotate proxy infrastructure for victim communications (via an HTML wrapper pointing victims to the *Session* messenger), complicating blocking and takedown efforts; Group-IB notes DeadLock also departs from typical double-extortion by lacking a public data-leak site and instead threatening underground data sales. Separately, Microsoft-observed phishing described by *KnowBe4* shows threat actors exploiting **email routing/spoofing misconfigurations** to make phishing appear internal (often leveraging **Tycoon2FA**), while ReliaQuest’s trend report and a separate write-up on **CastleLoader** describe human-driven initial access (spearphishing/drive-by) and social-engineering lures such as **ClickFix** being used to stage loaders and follow-on payloads—underscoring that access-broker and loader ecosystems continue to feed ransomware and broader intrusion activity.
Jun 29, 2026
Ransomware operators have been observed using **bring-your-own-vulnerable-driver (BYOVD)** techniques and custom anti-security tools to shut down endpoint protections before encrypting enterprise networks. Kaspersky documented a MedusaLocker intrusion in Brazil in which attackers accessed an SMTP server over RDP with valid administrative credentials, used **Mimikatz** to extract NTLM hashes, and moved laterally with pass-the-hash via PowerShell-based WMI and SMB execution before deploying a new AV-killer tool, `All.exe`. That tool loaded a renamed **TechPowerUp `ThrottleStop.sys`** driver (`ThrottleBlood.sys`), exploited vulnerable IOCTLs for physical memory read/write, hijacked kernel execution through `NtAddAtom`, and repeatedly terminated products from Microsoft Defender, CrowdStrike, SentinelOne, Sophos, Symantec, Bitdefender, ESET, Avast, AVG, McAfee, Panda, Quick Heal, and Kaspersky; the driver issue was assigned **`CVE-2025-7771`**. A separate report on **The Gentlemen** ransomware described a similar pattern in enterprise attacks across the Asia-Pacific region, where the group likely gained entry through an exposed FortiGate device or stolen credentials, then conducted Active Directory reconnaissance, used **PsExec** for lateral movement, established persistence with **AnyDesk**, abused **GPO** and **NETLOGON** for domain-wide deployment, and exfiltrated data with **WinSCP** for double extortion. TrendAI said the group evolved from generic anti-AV tooling to customized variants tailored to the security products installed in each victim environment, while also disabling Windows Defender and recovery mechanisms before dropping `README-GENTLEMEN.txt` and encrypting files with the `.7mtzhh` extension. Together, the incidents show ransomware crews increasingly pairing credential abuse and lateral movement with vulnerable-driver abuse and bespoke defense evasion to maximize encryption success.
Aug 21, 2026
Ransomware operators have repeatedly used tools and policy abuse to disable Microsoft Defender before encrypting Windows environments. DFIR reporting documented the freeware utility **Defender Control** being used in real intrusions by groups such as **Dharma**, **Phobos**, and **Crysis**, typically after access through exposed RDP, to turn off Defender through registry edits, service changes, driver unloading, and local group policy modifications. Separately, **LockBit 2.0** automated the same objective at enterprise scale by creating malicious Active Directory group policies on a domain controller, disabling Defender across domain-joined systems, and launching ransomware via scheduled tasks after enumerating hosts with AD and LDAP queries. More recent intrusions show the tactic evolving beyond simple utilities into **BYOVD** and broader policy abuse. WithSecure reported that the **CrazyHunter** ransomware actor used the vulnerable **Zemana Anti-Logger** driver `zam64.sys` to disable both Windows Defender and Trend Micro during attacks on Taiwanese hospitals and industrial organizations, including the Mackay Memorial Hospital incident. The operation also used publicly available tooling such as **SharpGPOAbuse** for lateral movement and persistence, reinforcing that defense evasion through Defender tampering and group policy manipulation remains a practical, low-barrier technique for ransomware actors ranging from smaller crews to more organized operators.
Aug 14, 2026