malicious file Archives

Winsage

February 11, 2026

Microsoft fixes six actively exploited flaws in latest Windows 11 update

Microsoft's February 2026 Patch Tuesday addressed 59 vulnerabilities in Windows 11, with six confirmed as actively exploited. The most critical vulnerability is CVE-2026-21510, a Windows Shell security feature bypass with a CVSS rating of 8.8, allowing attackers to evade warnings by tricking users into opening malicious files. Another significant vulnerability, CVE-2026-21513, also rated at 8.8, affects MSHTML and allows remote attackers to bypass execution prompts through malicious code in HTML or shortcut files. CVE-2026-21514 impacts Microsoft Word and enables adversaries to disable OLE mitigations, posing risks through document-based attacks. Two local privilege escalation vulnerabilities are CVE-2026-21519 in Desktop Window Manager and CVE-2026-21533 in Windows Remote Desktop Services, with CVSS scores of 7.8. CVE-2026-21525 is a denial-of-service vulnerability in Remote Access Connection Manager. The update includes 53 additional vulnerabilities across various Microsoft products and services, with CVE-2026-21531 in Azure SDK rated at 9.8 and CVE-2026-20841 affecting Windows Notepad rated at 8.8. The cumulative update for Windows 11 (KB5077181) also includes enhancements and resolves WPA3 Wi-Fi connectivity issues. Microsoft reminded users of the June 2026 expiration of Secure Boot certificates, which requires timely updates to ensure secure booting. Users can install the updates via Windows Update.

Tech Optimizer

January 19, 2026

PDFSIDER Malware Actively Used by Threat Actors to Bypass Antivirus and EDR Defenses

PDFSIDER is a sophisticated backdoor malware that bypasses modern endpoint detection and response systems. It is distributed through targeted spear-phishing campaigns that exploit vulnerabilities in legitimate PDF software. The malware is delivered via spear-phishing emails containing ZIP archives with a trojanized executable disguised as the PDF24 App. When executed, it uses DLL side-loading to load a malicious DLL (cryptbase.dll) alongside the legitimate PDF24.exe, allowing attackers to execute code without detection. PDFSIDER establishes encrypted command-and-control channels using the Botan 3.0.0 cryptographic library with AES-256 in GCM mode and operates mainly in memory to minimize detectable artifacts. It collects system information and executes commands through hidden cmd.exe processes. The malware employs advanced techniques to evade detection in sandbox and virtual machine environments, including checks for available RAM and debugger presence. Indicators of compromise include the malicious file cryptbase.dll and various clean files associated with the legitimate PDF24 application. Organizations are advised to enforce strict controls on executable files, provide user awareness training, and monitor DNS queries and encrypted traffic to detect PDFSIDER communications. The malware's behavior aligns with tactics used in state-sponsored espionage rather than financially motivated cybercrime.

AppWizard

December 22, 2025

Frogblight Malware Targets Android Users With Fake Court and Aid Apps

A new Android-based Trojan named Frogblight is targeting mobile users in Turkiye to steal funds from bank accounts. Identified by Kaspersky's Securelist in August 2025, it spreads through smishing, where scammers send deceptive SMS messages about legal court cases or financial aid. These messages often include links to download malicious applications disguised as legitimate support tools. The malware, which can conceal itself and deactivate on simulated devices or within the U.S., requests extensive permissions to access SMS messages and device storage. Once installed, it opens a legitimate government website to appear credible and injects JavaScript to record keystrokes during banking logins. Recent versions have added keylogging, contact list theft, and private call log collection. The malware has evolved to disguise itself as the Google Chrome browser and other tools, and its source code is available on GitHub, indicating it may be marketed as malware-as-a-service. Kaspersky advises users to avoid downloading APK files from untrusted sources and to scrutinize app permission requests.

Winsage

December 12, 2025

Windows Defender Firewall Service Vulnerability

On December 9, 2025, Microsoft addressed a vulnerability identified as CVE-2025-62468, which allowed an authenticated local attacker to access sensitive memory within the Windows Defender Firewall Service due to an out-of-bounds read in the service's memory handling routines. This flaw could expose heap or process memory, potentially revealing sensitive information. The vulnerability requires local authenticated access, raising concerns for both home users and system administrators. Microsoft classified the vulnerability as important, emphasizing the need for prompt action. Users are advised to update their systems through Windows Update to mitigate the risk. There is no confirmed public exploit for this vulnerability, and it does not allow remote code execution, but it can lead to information disclosure.

Winsage

December 10, 2025

U.S. CISA adds Microsoft Windows and WinRAR flaws to its Known Exploited Vulnerabilities catalog

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has expanded its Known Exploited Vulnerabilities (KEV) catalog to include two critical vulnerabilities: 1. CVE-2025-6218 (CVSS score of 7.8) - RARLAB WinRAR Path Traversal Vulnerability, which allows attackers to execute arbitrary code by manipulating file paths within a malicious archive or webpage. 2. CVE-2025-62221 (CVSS score of 7.8) - Microsoft Windows Use After Free Vulnerability, which enables an authorized attacker to elevate their privileges locally to SYSTEM. Federal agencies are required to address these vulnerabilities by December 30, 2025, in accordance with Binding Operational Directive (BOD) 22-01.

Tech Optimizer

November 14, 2025

Beware of Fake Bitcoin Tool That Hides DarkComet RAT Malware With it

A recent malware campaign has seen attackers disguising the DarkComet remote access trojan as Bitcoin-related applications to target cryptocurrency users. DarkComet RAT allows attackers to gain extensive control over compromised systems, despite its original creator discontinuing it years ago. The malware features capabilities such as keystroke logging, file theft, webcam surveillance, and remote desktop control, posing significant risks to users. The malicious file was distributed as a compressed RAR archive named “94k BTC wallet.exe,” which helps evade email filters. Security analysts at Point Wild discovered that the malware ensures persistence by copying itself to %AppData%RoamingMSDCSCexplorer.exe and creating a registry key for automatic execution at system startup. It attempts to connect to a command-and-control server at kvejo991.ddns.net over TCP port 1604. The malware injects its payload into legitimate Windows processes to perform keylogging and screen capture while remaining undetected. Captured keystrokes are stored in log files and exfiltrated through the command-and-control channel. Users are advised to avoid downloading cryptocurrency tools from untrusted sources and to keep security software updated.

Winsage

October 24, 2025

Microsoft Disables File Explorer Preview for Internet Files to Patch NTLM Vulnerability

Following the October 2025 Patch Tuesday updates, many Windows users experienced issues with the File Explorer preview pane, which stopped functioning for several file types. This change, implemented by Microsoft as a security enhancement, affects both Windows 11 and Windows 10 and is linked to a vulnerability associated with NTLM credential hashes. The updates, KB5066835 for Windows 11 and KB5066791 for Windows 10, disable the preview functionality for files marked with the "Mark of the Web" (MotW), indicating they originated from the internet. Instead of a preview, users receive a warning message about potential harm from the file. Microsoft has provided workarounds for users who wish to restore the preview functionality, including manually unblocking files or adjusting security settings for network shares, though these methods come with security risks. This change reflects a broader industry trend toward prioritizing security over user convenience.

Tech Optimizer

October 10, 2025

From infostealer to full RAT: dissecting the PureRAT attack chain

An investigation revealed that a Python-based infostealer campaign led to the deployment of PureRAT, a sophisticated remote access trojan (RAT). The campaign began with a phishing email containing a ZIP archive that included a legitimate PDF reader executable and a malicious DLL. The DLL executed a series of payloads, including a Python info-stealer that harvested sensitive data and exfiltrated it via the Telegram API. The attack progressed to a .NET executable, which employed techniques like process hollowing and evasion tactics to load additional payloads. The final payload, Mhgljosy.dll, was identified as PureRAT, which established an encrypted command-and-control (C2) channel and allowed for extensive control over the compromised host. The C2 server was traced to Vietnam, suggesting a connection to the PXA group. The malware's functionality included host fingerprinting, command execution, and potential access to sensitive information and resources. Indicators of compromise included specific file hashes, registry keys, and IP addresses associated with the C2 server.

Tech Optimizer

September 25, 2025

LNK Malware Leverages Windows Binaries to Evade Security Tools and Run Malicious Code

Cybersecurity researchers have identified a malware campaign utilizing Windows shortcut (.LNK) files distributed via Discord to deploy a Remote Access Trojan (RAT). The malicious file, named “cyber security.lnk,” lures users with a fake job offer PDF while executing PowerShell commands in the background. It displays a decoy document titled “Cyber Security.pdf” to distract victims during the infection process. The malware exploits the legitimate Windows utility odbcconf.exe to execute a malicious DLL named Moq.dll without triggering security alerts. A PowerShell script extracts a ZIP file containing the payload and runs it using the command: odbcconf.exe /a {regsvr "C:UsersPublicNugetmoq.dll"}. This approach bypasses standard security measures by utilizing trusted binaries. Moq.dll employs advanced evasion techniques, including modifying the AmsiScanBuffer function to disable the Anti-Malware Scan Interface (AMSI) and altering the EtwEventWrite function in ntdll.dll to prevent monitoring through event logs. The malware ensures persistence by modifying the Windows registry to run with explorer.exe at user login and communicates with its command and control server at hotchickenfly.info. The RAT can capture screenshots, gather system information, and exfiltrate data via Dropbox’s API, using AES encryption for its communications. This threat was first observed in Israel and highlights the trend of malware authors leveraging legitimate Windows tools to evade detection. Security researchers from K7 Labs have identified the malware and recommend application whitelisting and monitoring of LOLBin usage as countermeasures. Indicators of Compromise (IOCs) include specific hash values associated with the Trojan.

AppWizard

August 26, 2025

77 Malicious Android Apps With 19M Installs Targeted 831 Banks Worldwide

Zscaler’s ThreatLabz team identified 77 malicious applications on the Google Play Store with over 19 million installations, which target financial institutions and compromise user data. A new variant of the Anatsa banking trojan, also known as TeaBot, now targets over 831 banks globally, up from 650, and has expanded its reach to countries like Germany and South Korea. Many of these apps disguise themselves as document readers, with some exceeding 50,000 downloads. The malware downloads the Anatsa payload after installation and uses Android’s Accessibility Services to automate malicious activities, including stealing financial information and facilitating fraudulent transactions. The malware employs techniques to evade detection, such as obfuscating its code and using corrupted ZIP archives. The most prevalent Android malware identified was Joker, found in nearly 25% of the analyzed applications, known for stealing contacts and device data. A smaller subset of apps contained “maskware,” which engages in credential theft and personal data collection.