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.
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.
Two Arrests, One Supply-Chain Attack, and a Lot of Stolen Credentials
AFP charges two men over TeamPCP open-source supply-chain attacks that stole 500,000+ credentials from 1,000+ organizations via four malware families.
Australian police charged two Western Australian men as principal participants in TeamPCP, which allegedly inserted malicious code into open-source software to steal credentials and sensitive data from government, academia, and private sector organizations worldwide. The campaign compromised more than 1,000 organizations, harvested over 500,000 credentials, and exfiltrated at least 300 GB of data, with remediation costs in the hundreds of millions of dollars. Four malware families were deployed: CanisterWorm (cloud token harvesting), SANDCLOCK (AWS and Kubernetes credential theft), Mini Shai-Hulud (self-replicating npm/PyPI worm), and Miasma (credential-harvesting worm variant). Trojanized tools included Trivy, KICS, LiteLLM, and the Telnyx Python SDK, with exfiltration via GitHub repositories tpcp-docs and docs-tpcp.
The extension you never installed: KREMLIN forges Chrome's own integrity checks to steal banking sessions
Elastic details KREMLIN, a Brazilian banking malware whose malicious Chrome/Edge extension forges Chromium integrity checks to steal sessions.
Elastic Security Labs tracked operation REF9334 and its KREMLIN toolkit, a Brazilian banking malware campaign impersonating twelve banks across seven campaigns since May 2025. The infection chain uses multi-stage obfuscated JavaScript loaders with sandbox checks (file and process counting), scheduled-task persistence, and an Ethereum smart contract acting as a dead-drop resolver for C2 and payload URLs, abusing Archive.org for hosting. The malicious browser extension bypasses Chromium integrity mechanisms by manipulating Secure Preferences and regenerating required HMACs and App-Bound encrypted hashes. Threat Command disrupted over 1,500 infections by registering the kill-switch canary domain.
Cisco FMC flaws exploited by ransomware gang, state-sponsored hackers
Cisco Talos confirms ransomware and state-sponsored groups exploited CVE-2026-20079 and CVE-2026-20316 in Secure Firewall Management Center, deploying Qilin ransomware and Cyclops Blink.
Cisco Talos identified three threat clusters (UAT-12197, UAT-11823, UAT-11988) exploiting CVE-2026-20079, a CVSS 10.0 authentication bypass, and CVE-2026-20316, a CVSS 5.3 static-credential flaw, in Cisco Secure Firewall Management Center. Qilin affiliates used static credentials for reconnaissance and deployed Qilin ransomware; a Sandworm-linked cluster deployed a Cyclops Blink backdoor via a malicious license.tmp file; a third cluster stole credentials through a JSP web shell. Cisco has released hotfixes and urges immediate installation, with broader patches expected next week.
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.
Malicious LiteLLM Releases Tied to Trivy Hack May Have Exposed 2,100+ Organizations
Malicious LiteLLM 1.82.7/1.82.8 PyPI releases tied to the Trivy TeamPCP campaign harvested cloud, SSH, and database credentials, potentially exposing 2,500+ organizations.
CloudSEK reported that two malicious LiteLLM releases on PyPI (versions 1.82.7 and 1.82.8, live about 40 minutes on March 24) harvested cloud keys, SSH keys, Kubernetes tokens, and database passwords, with captured loot files mapping potential exposure to more than 2,500 organizations including NVIDIA, Cisco, Deloitte, Volkswagen, FedEx, Siemens, and X Corp. The campaign is part of TeamPCP (tracked by Google as UNC6780), linked to the Aqua Security Trivy scanner compromise tracked as CVE-2026-33634 and added to CISA's Known Exploited Vulnerabilities catalog on March 26. The payload used a litellm_init.pth file executed at Python interpreter startup and exfiltrated secrets to models.litellm[.]cloud; the FBI's FLASH-20260702-01 advisory urged rotation of CI/CD, publishing, and cloud credentials.
7th September – Threat Intelligence Report
Check Point weekly bulletin: exploited SonicWall SMA 1000 zero-days (CVE-2026-83548/49), JFrog Artifactory auth bypass, and a 2.8M-patient Baylor Genetics breach.
Check Point's weekly bulletin covers breaches including Thomson Reuters' C-Track platform (court records across 11 US states and Canada), Baylor Genetics (2.8M patients and employees, SSNs included), Hit casinos in Slovenia, and Dropbox (~5,000 accounts via abused Lenovo email verification). SonicWall patched two exploited SMA 1000 zero-days, including CVE-2026-83548, a CVSS 10.0 pre-authentication SSRF, while JFrog fixed exploited authentication bypass CVE-2026-82329 (CVSS 9.8). Malware and actor coverage includes Gambling Goblin, JSCeal, Mirage Kitten's NodeRabbit/PollCat campaign, and DPRK Contagious Interview macOS activity, plus a FalconFlank privilege-escalation PoC against CrowdStrike Falcon.
N-able Issues Fourth N-central Hotfix in Five Weeks for Unauthenticated RCE Flaw
N-able shipped Hotfix 4 for a CVSS 10.0 unauthenticated RCE (CVE-2026-86218) in N-central RMM, with conflicting statements on exploitation.
N-able released 2026.3 Hotfix 4 (build 2026.3.1.14) fixing CVE-2026-86218, a static code injection weakness (CWE-96) scored 10.0 on CVSS 4.0 that enables pre-authentication remote code execution on on-premises N-central RMM servers. Hosted NCOD instances are already patched; N-able's incident notice says the flaw was observed exploited in the wild while its release notes say exploitation is unconfirmed. Huntress, which has tracked N-central attacks since August, advises IP allowlisting, VPN-only access, or taking internet-reachable servers offline until patching. It is the fourth hotfix in five weeks, following fixes for CVE-2026-86206 and CVE-2026-86207, which CISA added to its Known Exploited Vulnerabilities catalog.