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21 stories in the last 30d

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Hackers deploy Linux rootkit on F5 BIG-IP APM devices, hiding web shell in memory

Sophos analyzed a Linux rootkit, tracked as PoisonedRefresh, on hacked F5 BIG-IP APM devices hiding an in-memory web shell linked to exploited CVE-2025-53521.

Sophos and ESET analyzed an implant (named PoisonedRefresh by ESET) deployed on compromised F5 BIG-IP APM appliances, which serves enterprise, financial, government, and public sector deployments. The second-stage payload intercepts __libc_start_main, hooks Apache's APR module loader (apr_dso_load), RC4-encodes key strings, and rewrites PHP file reads in memory to embed a web shell inside legitimate scripts like apm_css.php3, full_wt.php3, and webtop_popup_css.php3, leaving on-disk files unchanged. A related installer component infects /usr/sbin/httpd, persists across BIG-IP upgrade images, modifies SELinux configuration, and deploys the payload. The malware also creates a Unix domain socket at /run/bigtlog.pipe that hands authenticated local connections to /bin/bash; F5 links the activity to CVE-2025-53521, an unauthenticated RCE in BIG-IP APM already exploited in the wild.

Help Net Security · 7d agoMalware in the wildCVE-2025-535211

F5 BIG-IP APM Malware Injects a PHP Web Shell Into Memory, Evading Disk Scans

Sophos found F5 BIG-IP APM malware that injects a PHP web shell into Apache's memory, evading disk scans, linked to exploited CVE-2025-53521.

Sophos's September 7 analysis describes malware tied to F5's c05d5254 activity that hooks apr_dso_load, modifies the libphp PHP module in memory, and injects a PHP web shell when Apache loads apm_css.php3, full_wt.php3 or webtop_popup_css.php3, leaving on-disk files clean. A separate installer infects /usr/sbin/httpd and umount, runs before Apache starts, disables SELinux (per ESET's related PoisonedRefresh analysis), and opens a local socket at /run/bigtlog.pipe for shell access. The activity is linked to CVE-2025-53521 in BIG-IP APM, rated 9.8 CVSS 3.1, patched in October 2025, added to CISA KEV on March 27, 2026.

The Hacker News · 7d agoMalware in the wildCVE-2025-53521

PoisonedRefresh: A Fileless Linux Rootkit That Injects PHP Web Shells Into F5 BIG-IP APM Server Memory

Sophos details PoisonedRefresh, a fileless Linux rootkit that injects a memory-resident PHP web shell into F5 BIG-IP APM after exploitation of CVE-2025-53521.

On September 8, 2026, SophosLabs published an analysis of Linux/Agnt-IC (dubbed PoisonedRefresh by ESET) found in compromised F5 BIG-IP Access Policy Manager environments. Initial access leverages CVE-2025-53521, an unauthenticated RCE in BIG-IP APM when an access policy is configured on a virtual server; F5 confirmed exploitation and links the activity to cluster c05d5254, while Shadowserver observed 795 exposed vulnerable endpoints. A first stage hidden in a modified umount binary modifies /usr/sbin/httpd and SELinux configuration and embeds itself in BIG-IP upgrade images for persistence. The second-stage ELF intercepts __libc_start_main, hooks apr_dso_load, and injects a PHP web shell into libphp memory via mmap manipulation, leaving no disk artifacts, and exposes a /bin/bash shell via a local UNIX domain socket instead of a TCP port.

Security Affairs · 7d agoMalware in the wildCVE-2025-53521

Stealth rootkit targeting F5 BIG-IP could expose enterprise identity gateways

Sophos analyzed a stealth Linux rootkit that hides a web shell in memory on compromised F5 BIG-IP APM identity gateways, evading file-based detection.

Sophos analyzed a second-stage Linux rootkit implant found in compromised F5 BIG-IP APM environments running Apache and PHP, linked to exploitation of CVE-2025-53521, an unauthenticated RCE. The implant hooks Apache's PHP-loading process and serves modified in-memory versions of three legitimate webtop PHP files (apm_css.php3, full_wt.php3, webtop_popup_css.php3), leaving on-disk files untouched so hashes and integrity checks pass. It also establishes access via an authenticated local UNIX socket that can provide an interactive /bin/bash session. Experts warn compromised APM appliances, which handle federated SSO and terminate TLS at enterprise perimeters, could enable SSO token theft and lateral movement to trusted downstream applications.

CSO Online · 6d agoMalware in the wildCVE-2025-53521

Hackers breach F5 BIG-IP APM devices to deploy Linux rootkit

Sophos analyzed a Linux rootkit on F5 BIG-IP APM devices that injects a fileless PHP web shell, likely after CVE-2025-53521 exploitation.

Sophos analyzed a Linux rootkit targeting F5 BIG-IP APM environments, also tracked by ESET as PoisonedRefresh, which hijacks Apache's apr_dso_load module loader to inject a fileless PHP web shell into memory. The implant intercepts __libc_start_main, hides strings with RC4, creates a password-protected local UNIX socket backdoor for interactive Bash access, and persists across BIG-IP upgrade images while modifying SELinux configuration. It is likely a second-stage payload following exploitation of CVE-2025-53521, a critical RCE flaw F5 reclassified from a DoS issue in March. The ShadowServer Foundation tracked 795 F5 BIG-IP APM endpoints exposed online.

BleepingComputer · 7d agoMalware in the wildCVE-2025-53521

Malcious Admin Menu Editor Pro plugin backdoors 1,500 WordPress sites

Compromised Admin Menu Editor Pro update server distributed backdoored plugin versions installing web shells and hidden admin accounts on roughly 1,500 WordPress sites.

A threat actor with root-level access to adminmenueditor.com pushed trojanized Admin Menu Editor Pro versions 2.35 and 2.36 containing includes/wp-user-consent.php, which installed a web shell and created a hidden wp_-prefixed user account. At least 230 customers and roughly 1,500 sites installed the malicious update, with several hundred more downloads possibly affected. Developer Janis Elsts took the site offline after the attacker recompromised the clean 2.36 release; version 2.34 and the free plugin are believed unaffected.

BleepingComputer · 20h agoMalware in the wild1

Chinese-Speaking Hackers Use Noodle RAT Backdoor to Spy on Windows and Linux Systems

Chinese-speaking actors use cross-platform Noodle RAT backdoor to maintain covert access to Windows and Linux systems across Asia-Pacific.

Noodle RAT (also ANGYREBEL/Nood RAT) has been active since at least mid-2016 and was long misidentified as Gh0st RAT or Rekoobe variants until Trend Micro and Cyberint classified it as a distinct multi-platform family. The Windows build (Win.NOODLERAT) is an in-memory modular shellcode backdoor delivered via MULTIDROP and MICROLOAD loaders, while the Linux build supports reverse shells, SOCKS tunneling, and cron persistence after web shell or public-facing service exploitation. It has appeared in intrusions in Thailand, India, Japan, Malaysia, and Taiwan and is linked to Iron Tiger, Calypso APT, Rocke, and Cloud Snooper campaigns spanning espionage and cybercrime. Recently discovered Linux builders 1.0.1 and 1.0.2 indicate the toolkit remains actively maintained.

GBHackersupdated · 3h agofirst · 4h agoMalware in the wild 2 sources

Microsoft Links 30+ Rotating Domains to MacSync Stealer Infrastructure

Microsoft links 30+ rotating domains to the MacSync macOS infostealer, confirming active credential and file exfiltration through chunked HTTP PUT uploads.

Microsoft Defender Experts correlated 30+ domains with MacSync Stealer, requiring aligned endpoint and network behaviors (process ancestry, command-line patterns, /curl/, /dynamic?txd=, and /gate?buildtxd= paths, API-key headers, chunked HTTP PUT parameters) to link infrastructure. Execution begins from an interactive zsh session consistent with ClickFix social engineering, with curl retrieving and Base64/gunzip decoding the payload, followed by collection of Keychain data, browser credentials, SSH keys, AWS credentials, Kubernetes configs, and Apple Notes. Data is zipped to /tmp/osalogging.zip, chunked, uploaded via HTTP PUT, and artifacts are deleted afterward; the analysis builds on RST Cloud's May 8 findings and overlaps with Microsoft's earlier 250+ domain ClickFix campaign distributing MacSync and Atomic Stealer (AMOS).

The Hacker News · 28d agoMalware in the wild

PEEP Turns Chrome and Edge Into Post-Compromise Backdoors for Host Command Execution

SOCRadar disclosed PEEP, a post-exploitation Chromium extension toolkit that turns Chrome and Edge into host-level backdoors via native messaging and C2 polling.

SOCRadar researchers detailed PEEP, a Chromium-based post-exploitation toolkit masquerading as a 'Smart Bookmarks' extension injected directly into Chrome and Edge profiles by forging Secure Preferences integrity values, bypassing Web Store checks. A native-messaging host binary (nm_host.exe) extends the browser agent to host-level command execution, file management, credential theft, and session hijacking, while the extension polls C2 endpoints at 206.237.30.232 or xfjcc.fun every 30 seconds over plaintext HTTP and exfiltrates browsing history, cookies, and tab metadata. PEEP is derived from the open-source RedExt red teaming framework, adds PowerShell persistence scripts, and includes a Linux-targeting Python script, suggesting cross-platform intent. The activity is unattributed but contains Chinese-language artifacts; a C2 /health endpoint showed 34 agent entries and 10 active sessions.

The Hacker News · 8d agoMalware in the wild1

New KATARU IoT Malware Packs Linux Privilege Escalation Exploits and Mirai-Style DDoS Attacks

Nozomi Networks identified KATARU, a new Mirai-style IoT botnet delivered via Telnet brute force that uses Linux privilege-escalation exploits and encrypted C2 for DDoS floods.

Nozomi Networks identified KATARU in August after a Telnet password-guessing attack against a honeypot retrieved an ARM payload. The malware attempts exploits for CVE-2026-46300 (Fragnesia), CVE-2026-43284 (DirtyFrag), and CVE-2026-31431 (Copy Fail), plus a cgroup v1 release_agent escape, and persists via systemd services, cron tasks, rc scripts, OpenWrt hooks, and Android boot locations. Its C2 uses X25519 key exchange with ChaCha20-Poly1305 encryption and supports TCP, UDP, ICMP, HTTP, QUIC, and DNS floods, plus SSH brute forcing and command execution; embedded exploit shellcode in the ARM build targeted x86, suggesting untested copied code.

Cyber Security News · 5d agoMalware in the wild 2 sourcesCVE-2026-46300CVE-2026-43284CVE-2026-31431

GoCaracal Malware Uses Ethereum Smart Contract to Fetch Replacement C2 Address

Arctic Wolf links new Go-based GoCaracal malware with Ethereum smart-contract C2 fallback to Dark Caracal, targeting a Venezuelan communications organization.

Arctic Wolf assessed with medium confidence that a June 2026 intrusion at an unnamed Venezuelan communications organization used GoCaracal, a previously undocumented Go-based malware framework linked to Dark Caracal. The lightweight profile provides encrypted C2, interactive shell access, and shellcode injection; the extended profile adds browser data theft, keylogging, WebRTC remote desktop, and SOCKS5 proxying. When the primary C2 server is unreachable, the malware queries an Ethereum smart contract via eth_getStorageAt at public JSON-RPC endpoints to fetch a replacement C2 address. Bandook was deployed in parallel, and Arctic Wolf published a YARA rule and indicators of compromise.

The Hacker News · 20d agoMalware in the wild1

ThreatsDay: 296K IoT Botnet, 100+ Water Systems Targeted, SharePoint RCE Chain + 27 New Stories

Weekly ThreatsDay bulletin details a ShinyHunters-style social engineering hit on ReliaQuest, the 296,000-device Dysphoria IoT botnet, and several new malware families.

ReliaQuest confirmed a social engineering attack on August 22, 2026, in which an attacker used a fake SSO page and MFA push approval to gain brief view-only access to an identity dashboard, with tactics matching ShinyHunters, which has since listed the firm on its leak portal. The Shadowserver Foundation reported the Dysphoria botnet has compromised nearly 296,000 IoT devices for DDoS attacks and recently added residential proxy capability. Cisco Talos documented JWR, an operator-driven phishing-as-a-service framework linked to The Outsider that harvests credentials, identity documents, and 2FA codes over an encrypted WebSocket. New malware coverage includes the Octagon Android fraud bot ($1,400/month), the C2Looper Rust backdoor delivered via ClickFix, and the Aeternum loader that moved C2 to the Polygon blockchain.

The Hacker News · 14d agoMalware in the wild

Sandworm-Linked Cyclops Blink Returns With Network Scanning and Packet-Sniffing Capabilities

Sophos uncovers a 64-bit Cyclops Blink variant on hacked Cisco FMC appliances, adding internal network scanning and selective packet capture; linked to Sandworm.

Sophos CTU analyzed a new 64-bit x86-64 Cyclops Blink implant (timezone_check) deployed on Cisco Secure Firewall Management Center appliances compromised via CVE-2026-20079 authentication bypass and CVE-2026-20316 low-privileged login. The activity is assessed with high confidence as Russian-nexus, with a moderate-confidence link to Sandworm (IRON VIKING, also tracked as Seashell Blizzard). The implant runs a parent controller plus five worker modules, masquerades as [kworker/0:1], persists via SysV init scripts at /lib/tz/timezone_check, and beacons to hard-coded C2 89.34.96.56 over a custom TLS protocol on ports 43856 and 49172. New module 0x11 scans internal IPv4 networks for SSH, SMB, LDAP, VMware, HTTP/HTTPS and VPN services, while module 0x12 performs filtered packet capture that can expose cleartext credentials, cookies and tokens.

GBHackers · 2d agoMalware in the wild 11 sourcesCVE-2026-20079CVE-2026-20316

VectraRAT Malware-as-a-Service Lets Hackers Bypass UAC and Hijack Windows Systems

New VectraRAT malware-as-a-service at $250/month combines RAT capabilities, credential theft, clipboard hijacking, and a UACME-based UAC bypass; 38 victims observed.

VectraRAT is a previously undocumented MaaS platform with a Go-based VectraHub Linux C2 server embedding a Vue3 operator panel and a C++ Windows implant, rented from $250/month and linked to the aliases Vectra and Nyxel. It communicates over TCP port 3308 via a proprietary MessagePack protocol, steals browser and file-based credentials, and abuses UACME method 41 with debug-object handle hijacking via winver.exe and computerdefaults.exe. SOCRadar identified 38 live victim sessions in one week, 48% on corporate Windows editions, with delivery via the Amadey loader and ClickFix pages impersonating TurboTax.

GBHackersupdated · 2h agofirst · 4h agoMalware in the wild 3 sources

Fake GTA 6 download delivers malware-packed bundle to impatient gamers

Huntress found malware disguised as a leaked GTA 6 download bundling NJRAT, DCRAT, an infostealer, and Chaos ransomware used as a wiper.

Huntress analyzed a fake Grand Theft Auto VI ISO whose gta6installer.exe displays a fake 'License not found' error while silently installing payloads. The bundle includes NJRAT and DCRAT remote access trojans, the Mercurial Grabber infostealer, and a Chaos ransomware variant used destructively as a wiper, plus a Yandex Browser drop. The Chaos variant encrypts files up to 200MB, overwrites larger ones, deletes shadow copies, and disables recovery, with no ransom actually demanded. Most components are old malware dating to 2023 and are detected by up-to-date Windows Defender.

Help Net Securityupdated · 6d agofirst · 6d agoMalware in the wild 3 sources1

E4del and PINHOLE RATs Turn FTP Banners Into Dead Drops for Malware Commands

Researchers identified two new RATs, E4del and PINHOLE, using FTP banners as dead drop resolvers to fetch C2 commands via ClickFix-style lures.

SOCRADAR documented two previously unreported RATs, E4del and PINHOLE, that use FTP banners as dead drop resolvers, a first in-the-wild use of this technique. E4del is a Node.js-based RAT hidden in a digitally signed Electron application masquerading as Discord, with tiered-jitter beaconing, reverse shell, screenshot capture and desktop streaming. PINHOLE is more advanced, using Pinterest, SurveyMonkey and Cloudflare Workers for C2 resolution, six layers of unpacking, Halo's Gate EDR evasion and Early Bird APC injection. A related WebDAV delivery chain overlaps with ClearFake campaigns distributing WordlistLoader and Amatera Stealer.

The Hacker News · 22d agoMalware in the wild

Atomic macOS (AMOS) Stealer Activity

Unit 42 details an August 2026 AMOS macOS stealer infection delivered via fake 'macOS toolkit' pages and Terminal paste commands, exfiltrating credentials to C2.

Unit 42 analyzed an AMOS (Atomic macOS Stealer) infection from August 5, 2026, initiated via a page at getmacouscloud[.]com instructing users to paste a command into Terminal. The command fetched a Zsh script from ferncore13[.]com that delivered a Mach-O installer to /tmp/helper and supporting files under /Library/Application Support/.com.apple.accountsd/ and .com.apple.metadata.mds/. AMOS collected browser data, credentials, cryptocurrency wallets (Binance, TonKeeper), Telegram data, and FileGrabber content such as AWS and gcloud files, uploading it via HTTP POST to C2 server 161.35.146[.]120. AMOS has been advertised on Telegram since April 2024 and distributed via ClickFix campaigns, malicious ads, and cracked-software sites.

Palo Alto Unit 42 · 7h agoMalware in the wild

Hackers Use Fake Claude and ChatGPT Installers to Infect Mac Users With Password-Stealing Malware

Attackers distribute MacSync macOS infostealer via fake Claude and ChatGPT installers and sponsored search ads, stealing passwords, cookies, keys, and wallets.

SEQRITE reports a malware-as-a-service campaign pushing MacSync, a macOS password stealer, through sponsored search results and fake Claude and ChatGPT download pages. ClickFix-style prompts trick users into pasting a Terminal command that launches a stager, which loads an in-memory AppleScript to harvest credentials. The malware collects browser vaults, Keychain data, SSH keys, session cookies, messaging sessions, and cryptocurrency wallets, then persists via renamed LaunchAgents and can request screen-recording permissions.

Cyber Security News · 6d agoMalware in the wild 2 sources

Grand Theft Auto VI hype leads to malware

Fake GTA6 ISO downloads spread via SEO poisoning, torrents, and forums deliver NJRAT, DCRAT, an infostealer, and wiper ransomware.

Huntress analyzed a malicious ISO masquerading as a leaked Grand Theft Auto VI build; there is no official GTA6 demo or leaked playable copy. The fake gta6installer.exe shows a Russian 'license' message asking victims to email the attacker if the crack fails, then drops GTA6-branded files into %TEMP%. It installs multiple repurposed NJRAT copies (2023-era files) connecting to AWS-hosted IPs 35.157.111.131, 3.68.56.232, 3.67.15.169 and an ngrok tunnel, plus DCRAT communicating with a0700877.xsph.ru (141.8.197.42). The bundle also includes an infostealer and ransomware used as a wiper, in what appears to be an opportunistic, everything-at-once campaign.

Huntress · 7d agoMalware in the wild

Hackers Hijack HBO Max Reddit Account to Push 108 ClickFix Malware Ads

Hijacked verified HBO Max Reddit account ran 108 ClickFix malvertising ads delivering AMOS infostealers, Windows loaders, and crypto clipboard hijackers.

HudsonRock and ADAMnetworks identified a cross-platform ClickFix operation dubbed PasteSwitch that abused the compromised verified Reddit account u/hbomax to publish 108 malicious ads over 48 hours, using domains like hbomaxx[.]us and codex-craft[.]com. macOS victims run curl/zsh commands delivering AMOS-related stealers and fake wallets, while Windows users get an InstallFix route using mshta and PowerShell that loads Amatera in memory and disables AMSI. The operation's AnimateClipper and ZigClipper families hijack clipboards to swap cryptocurrency addresses, with C2 domains rotated via Binance Smart Chain contracts. Reddit paused the ads and is investigating.

Cyber Security Newsupdated · 1d agofirst · 1d agoMalware in the wild 7 sources

Muhstik Botnet Attacks Tomato Routers to Harvest New IoT Devices

Unit 42 found a Muhstik botnet variant brute-forcing Tomato router web authentication to harvest IoT devices for crypto mining and DDoS attacks.

Palo Alto Networks Unit 42 researchers in December 2019 identified a new Muhstik botnet variant scanning Tomato routers on TCP 8080 and brute-forcing default admin credentials, targeting roughly 4,600 exposed devices found via Shodan. The variant also scans WordPress and Webuzo installations and exploits the Oracle WebLogic deserialization flaw CVE-2019-2725 for unauthenticated remote code execution. Muhstik, active since March 2018, self-propagates like a worm and typically monetizes infections through cryptocurrency mining and DDoS attacks controlled via an IRC C2 channel.

Palo Alto Unit 42 · 28d agoMalware in the wildCVE-2019-2725