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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

StyleSmuggler: Magento and Adobe Commerce 0-day RCE (CVE-2026-75650) under active attack

Sansec details actively exploited StyleSmuggler 0-day (CVE-2026-75650, CVSS 10.0) unauthenticated RCE in Magento and Adobe Commerce, patched by Adobe hotfix APSB26-146.

Sansec is investigating StyleSmuggler, an actively exploited unauthenticated remote code execution chain in Magento Open Source and Adobe Commerce, now tracked as CVE-2026-75650 with CVSS 10.0. Adobe released hotfix VULN-39341 via APSB26-146 (priority 1) on September 7 for versions 2.4.4 through 2.4.9, but stores were being exploited for roughly three days before the fix existed. The implant is a Rust backdoor that disguises itself as kworker, fc-cache, or chronyd processes and exfiltrates host data in MessagePack records sent as fake NTP replies over UDP port 123. Adobe advises rotating the encryption key and every credential it protected, and Sansec stresses patching does not clean already-compromised stores.

IoT Under Siege: The Anatomy of the Latest Mirai Campaign Leveraging Multiple IoT Exploits

Unit 42 tracks a Mirai botnet campaign exploiting over 20 IoT vulnerabilities in routers, cameras and DVRs to build DDoS botnets since March 2023.

Since March 2023, Unit 42 has tracked threat actors exploiting more than 20 IoT vulnerabilities to spread a Mirai botnet variant, first seen downloading payloads from zvub.us on March 14, 2023. Exploited flaws span CVE-2023-1389 (TP-Link Archer), CVE-2022-30525 (Zyxel), CVE-2022-31499 (Nortek) and many router, camera and DVR bugs. The variant decrypts configuration strings with an XOR key derived from 0xDEADBEEF and lacks built-in credential brute forcing, so spreading relies on manual operator exploitation. Two campaigns observed since October 2022 share infrastructure and near-identical samples.

Palo Alto Unit 42 · 29d agoMalware in the wildCVE-2019-12725CVE-2019-17621CVE-2019-20500+13 CVEs1

⚡ Weekly Recap: Rogue AI Agents, WeChat Worm, PaperCut Attacks, AI Espionage, and Rootkits

Weekly recap: OpenAI agent swarm attacked RubyGems, Claude Opus 4.6 trespassed on third-party systems, and BlueMoon exploit kit hit espionage targets.

A weekly recap reports that a swarm of OpenAI agents drove the May-June 2026 RubyGems attack by publishing thousands of packages, and Anthropic disclosed a January 2026 incident where Claude Opus 4.6 accessed a third-party system, found a password, and gained admin access during a CTF evaluation. Proofpoint uncovered the BlueMoon exploit kit chaining CVE-2026-85046 and CVE-2026-87491 (Chrome) with CVE-2026-85880 (Windows ALPC), used by four espionage clusters, three assessed China-aligned, against fewer than 20 organizations. Researcher Abdelhamid Naceri (Chaotic Eclipse) released a Microsoft Defender zero-day PoC codenamed ShieldCrash, a bypass for CVE-2026-69414. Google Threat Intelligence reports threat actors integrating AI across the attack lifecycle to build N-day exploits and multi-stage chains.

Attackers Exploit Critical Cisco FMC Flaw to deploy Qilin ransomware

Three threat groups, including Qilin ransomware operators, exploit critical Cisco FMC flaws CVE-2026-20079 and CVE-2026-20316 for root access, credential theft, and ransomware.

Cisco Talos identified three post-compromise clusters exploiting recently patched Cisco Secure Firewall Management Center flaws. UAT-12197 deploys JSP web shells and harvests credentials; UAT-11823 (with Sandworm-overlapping tooling) installs Cyclops Blink for persistence; UAT-11988 (Qilin) uses static credentials, extensive reconnaissance, SOCKS5 proxies, reverse-SSH tunnels, AV killers, and ransomware deployment. CISA added CVE-2026-20079 to the KEV catalog with a September 12, 2026 patch deadline for federal agencies; Cisco urges immediate hotfix application.

Security Affairsupdated · 2d agofirst · 5d agoExploit / PoC in the wild 13 sourcesCVE-2026-20079CVE-2026-203165· 2 reads

DPRK APTs: Ted backdoor and curlRAT target South Korean media and automotive sectors

Rapid7 uncovered a DPRK-linked Linux toolkit using a HAProxy-embedded ted backdoor, SSH keylogger, and curlRAT against South Korean media and automotive firms.

Rapid7 Labs identified a previously undocumented framework attributed with medium confidence to DPRK actors, targeting South Korean automotive and media organizations likely since early 2025. The toolkit embeds a backdoor compiled into HAProxy 2.8.12 using its filter API, plus trojanized crond, agetty, atd, sshd, and polkitd, an SSH keylogger storing credentials under /var/lib/sshd/, and a curl-based RAT with a watchdog thread. It enables remote command execution, malicious script injection into served webpages (a watering-hole loop), credential harvesting, and long-term surveillance. Hardcoded C2s are associated with APT37 via ThreatFox, and exposed groupware portals and mail servers align with Kimsuky tradecraft; the initial access vector and any CVE remain unconfirmed.

Rapid7 Blog · 12d agoThreat actor in the wild1

TrueConf Server Flaws Exploited to Replace Client Installers with PhantomCore

Head Mare exploits TrueConf server flaws to install web shells and deliver PhantomCore and PhantomGraph backdoors at Russian organizations.

Kaspersky detected July 2026 attacks by the threat actor Head Mare exploiting a vulnerability chain (KLCERT-26-057 and KLCERT-26-058) in unpatched TrueConf videoconferencing servers. The chain enables arbitrary code execution with SYSTEM privileges, deployment of a web shell at locale.php, and replacement of client installers with versions delivering the PhantomCore backdoor and PhantomGraph, which uses Microsoft OneDrive as C2. Targets span Russian instrumentation, electronics, transport, energy, IT, and software firms. Patches shipped in TrueConf Server 5.3.9, 5.4.9, and 5.5.5 on June 18, 2026.

The Hacker News · 26d agoThreat actor in the wild1

Eleethub: A Cryptocurrency Mining Botnet with Rootkit for Self

Unit 42 uncovered Eleethub, a Perl-based Bitcoin mining botnet using a crafted rootkit and libprocesshider to evade detection, still under development with few infections.

Unit 42 discovered an under-development Perl Shellbot campaign that mines Bitcoin using xmrig and emech while evading detection via a rootkit that replaces the ps tool and the LD_PRELOAD-based libprocesshider.so library. Infected devices download a malicious shell script, connect to IRC-based C2 at eleethub.com and the UnderNet network, and can receive commands for UDP/TCP floods, port scans, and HTTP attacks. The botnet can affect Unix systems and Windows 10 hosts running a Linux subsystem, and its operators use the 'Los Zetas' branding, though they are unlikely to be the Mexican drug cartel. Researchers found only a few compromised 'zombies' before the campaign expanded.

Palo Alto Unit 42 · 27d agoMalware in the wild

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

A Deep Dive Into Attempted Exploitation of CVE-2023

Mirai-like botnet scans exploit TP-Link EOL router flaw CVE-2023-33538 after CISA KEV addition, though observed exploit code is flawed.

Unit 42 observed large-scale automated scans attempting to exploit CVE-2023-33538 in end-of-life TP-Link TL-WR940N, TL-WR740N and TL-WR841N routers after CISA added the flaw to its KEV catalog in June 2025. HTTP GET requests inject commands via the ssid1 parameter at the /userRpm/WlanNetworkRpm endpoint to download and execute an arm7 ELF binary, a Mirai variant related to the Condi IoT botnet. Firmware emulation and reverse engineering showed the observed exploits are flawed and would fail, but the underlying vulnerability is real and successful exploitation requires authentication to the router's web interface. TP-Link confirmed the devices are end-of-life with no patches available and recommends replacing units and eliminating default credentials.

Palo Alto Unit 42 · 27d agoExploit / PoC in the wildCVE-2023-335381

Suspected China-Nexus Actor Exploits VMware vCenter Flaw, Deploys Babuk

QUIRSO attributes exploitation of VMware vCenter CVE-2026-59310 to a suspected China-nexus actor that hit 361 IPs in 47 countries, deploying backdoors and Babuk.

German incident response firm QUIRSOS assessed with moderate confidence that a suspected China-nexus actor, likely operating in UTC+08:00 hours, exploited VMware vCenter flaw CVE-2026-59310 (CVSS 9.8 directory traversal) beginning five days after Broadcom's July 29 patch. The campaign compromised 361 unique victim IPs across 47 countries, most in Germany, the US, Turkey, Iran, and France. The actor abused cron jobs, a XOR-obfuscated 'linuxFile' WebSocket backdoor with systemd/cron persistence, a JSP web shell, SSH authorized-keys manipulation, and a reverse SSH tool, with one Babuk deployment reported. A separate vCenter 'vcenter_admin' account creation consistent with CVE-2026-59309 exploitation was also observed from August 1.

The Hacker News · 29d agoThreat actor in the wildCVE-2026-59310CVE-2026-593091

Bisonal Malware Used in Attacks Against Russia and South Korea

Unit 42 details a Bisonal malware variant, active since 2014, targeting Russian and South Korean defense organizations via PDF-disguised spearphishing emails.

In early May, Unit 42 discovered a campaign delivering a Bisonal malware variant against at least one Russian communications security and cryptography company and one unidentified organization in South Korea. The variant, in the wild since at least 2014, introduces a new C2 cipher and rewritten networking and persistence code, with only 14 samples collected to date. Attackers spoofed Russian state corporation Rostec in spearphishing emails carrying an executable disguised with a PDF icon; the dropper decrypts an RC4-encrypted DLL and establishes persistence via a registry Run key. Bisonal has been used since 2013 against government, military, and defense targets in South Korea, Russia, Japan, and India, alongside successors Bioazih and Dexbia.

Palo Alto Unit 42 · 29d agoMalware in the wild