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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 · 8d agoMalware in the wildCVE-2025-53521

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

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

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

ApateWeb: An Evasive Large-Scale Scareware and PUP Delivery Campaign

Unit 42 uncovers ApateWeb, a campaign using over 130,000 domains and multilayered redirects to deliver scareware, adware and PUPs to millions of users.

Unit 42 discovered ApateWeb, a large-scale campaign using a network of more than 130,000 domains to deliver scareware, potentially unwanted programs, adware including a rogue browser and browser extensions, and scam pages. The campaign uses a three-layer structure with deceptive emails as the entry point, centralized victim tracking via UUIDs, intermediate adware or anti-bot redirections, and evasion tactics such as cloaking, bot detection error pages, and wildcard DNS abuse. Activity spiked since August 2022, with several hundred attacker-controlled sites remaining in Tranco's top 1 million rankings and millions of monthly hits; Unit 42 blocked an estimated 3.5 million sessions across 74,711 devices in November 2023.

Palo Alto Unit 42 · Aug 17, 2026Phishing & fraud in the wild

OpenBMB Releases MiniCPM5-2B: A 2.52B Dense Model Averaging 53.9 Across 34 Benchmarks and Built to Run On Device

OpenBMB released MiniCPM5-2B, a 2.52B-parameter Apache 2.0 on-device model averaging 53.9 across 34 benchmarks, ahead of Qwen3.5-4B.

OpenBMB released MiniCPM5-2B, a 2,516,756,480-parameter dense LlamaForCausalLM model with grouped-query attention and a 131,072-token context, under Apache 2.0, runnable via vLLM, SGLang, llama.cpp, and Ollama. It averages 53.9 across 34 benchmarks versus 51.1 for Qwen3.5-4B, with strong tool-use (97.1 on tau2-Bench Telecom) and code results (69.1 LiveCodeBench v6, 46.4 SWE-bench Verified). Training combined 400B tokens of deep-thinking SFT, critic-based JustRL II RL teachers, and on-policy distillation merging 16 RL experts; datasets and intermediate checkpoints were published alongside the weights.

MarkTechPost · 9d agoModel release

[remote] PCMan 2.0.7 - Buffer Overflow

A remote buffer overflow in PCMan 2.0.7 has a public proof-of-concept exploit published on Exploit-DB.

Exploit-DB listing 52657 discloses a remote buffer overflow vulnerability in PCMan version 2.0.7. A proof-of-concept exploit is publicly available, allowing attackers to potentially crash or compromise affected instances. The listing includes no CVE identifier and reports no observed exploitation in the wild.

Exploit-DB · Aug 18, 2026Exploit / PoC1

Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of Service Vulnerability

Cisco warns of a DoS flaw in SIP software on Desk Phone 9800 and IP Phone 7800/8800 series from improper HTTP packet memory handling.

Cisco disclosed a denial of service vulnerability affecting Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 devices running Cisco SIP Software. An unauthenticated remote attacker can send a continuous stream of crafted HTTP packets, causing sustained memory consumption until the device becomes unresponsive. A manual reboot is required to recover an affected device. No CVE identifier was listed in the advisory text.

Cisco Security Advisories · 14d agoAdvisory

A Feature-Rich Embedded NIDS with eBPF/XDP: Detector and Architecture Trade-offs

eBPF/XDP-based NIDS with Isolation Forest reaches 0.965 live F1 on DDoS replay; gRPC microservices match monolithic accuracy within 2ms overhead.

The paper presents a DDoS-focused network intrusion detection system for transport networks built with Ericsson, combining a statistical baseline with an Isolation Forest trained on flow features from GoFlowMeter, an open-source Go implementation of CICFlowMeter, plus eBPF/XDP kernel-level traffic filtering. On a Raspberry Pi 5 testbed replaying CIC-DDoS2019 as real traffic, the Isolation Forest achieves 0.965 recall/F1 live in the monolithic variant, catching low-volume attack windows the baseline misses. gRPC microservices nearly match monolithic accuracy adding under 2ms per window, while the Kafka pipeline trails by roughly nine percentage points and adds about 27ms.

arXiv cs.CR · 5d agoResearch

153GB of stolen credentials surface after LiteLLM supply chain attack

153GB archive from the LiteLLM supply chain attack exposes secrets from about 2,500 companies, including AWS, Samsung, Cisco and Salesforce.

Hudson Rock obtained and analyzed a 153GB archive stolen in the LiteLLM supply chain attack, containing 433,909 files with secrets attributed to 2,488 corporate domains, including AWS, Samsung, Cisco, Salesforce, NVIDIA, Microsoft and Siemens. TeamPCP compromised Trivy on March 19, 2026, stole LiteLLM's PyPI publishing tokens through the build pipeline, and published malicious LiteLLM versions 1.82.7 and 1.82.8 on March 24. CloudSEK separately estimated close to 2,500 exposed organizations, and Kevin Beaumont confirmed the data is legitimate. Hudson Rock is running a global ethical disclosure effort and urges organizations to rotate secrets before the trove leaks publicly.

Help Net Security · Aug 13, 2026Data breach in the wild

New DDRop Attack Breaks Intel TDX and AMD SEV-SNP With $159 DDR5 Device

DDRop uses a $159 DDR5 RDIMM interposer to silently drop memory writes and break Intel TDX and AMD SEV-SNP confidential VMs.

Researchers published DDRop, a physical attack built from about $159 in parts that uses a custom DDR5 RDIMM interposer to inject parity errors and silently discard selected cache-line writebacks. Intel TDX, Intel Scalable SGX, and AMD SEV-SNP are affected because they lack per-line cryptographic freshness, so processors can accept stale encrypted data as valid state. The team demonstrated deterministic plaintext copying between pages, malicious Secure EPT entry injection, forcing trust domains into debug mode, and forging attestation measurements. The attack requires privileged host control plus brief physical access, and researchers say no simple software patch exists.

Cyber Security News · 1d agoResearch 2 sources

Cisco Industrial Ethernet 1000 Series Switches Denial of Service Vulnerability

Cisco released a fix for a management-plane flooding DoS in IE-1000 switches that can make the device manager, SSH, or API inaccessible.

Insufficient protection against management plane flooding in Cisco Industrial Ethernet 1000 Series Switches allows an unauthenticated remote attacker to send high-rate ICMP, SSH, or HTTP traffic, raising CPU usage and causing a denial-of-service condition on the device manager web GUI, SSH, or API. Data traffic through the device is not affected. Cisco has released software updates to address the issue.

Cisco Security Advisories · 28d agoAdvisory

openbmb/MiniCPM5-2B — new model trending #4 on Hugging Face

OpenBMB released MiniCPM5-2B, a dense 2B open-weights Transformer claiming 2B-class open-source SOTA for on-device deployment.

OpenBMB released MiniCPM5-2B, the second model in the MiniCPM5 series following MiniCPM5-1B, and it is trending #4 on Hugging Face. The dense 2B Transformer targets on-device, local, and resource-constrained deployment and claims 2B-class open-source SOTA while remaining competitive with 4B-class models. Reported strengths include coding, mathematics, long-context understanding, tool use, and agentic tasks; a tech report (arXiv 2506.07900), GitHub repo, and online demo accompany the release.

Hugging Face trending models · 10d agoModel release

Heap overflow in kernel driver due to missing size validation

Fortinet fixes a CVSS 7.3 heap overflow in the FortiClient Windows kernel driver enabling code execution via crafted DNS responses.

Fortinet PSIRT advisory FG-IR-26-156, revised 2026-08-12, describes a heap-based buffer overflow (CWE-120, buffer copy without checking input size) in the FortiClient Windows kernel driver, scored CVSSv3 7.3. An unauthenticated attacker positioned to alter or craft DNS responses for a targeted host could execute arbitrary code via malicious packets. No CVE identifier or exploitation status is provided in the advisory text, so administrators should check the full bulletin for affected versions and fixed releases.

Fortinet PSIRT · Aug 12, 2026Advisory

MacOS 27 - First Boot, (Tue, Sep 15th)

SANS ISC documents the expected network traffic macOS 27 'Golden Gate' generates on first boot to help defenders baseline their networks.

Johannes Ullrich of SANS Internet Storm Center captured roughly 300 packets from a macOS 27 'Golden Gate' system before user login, covering DHCP, IPv6 duplicate address discovery, DNS, and TCP behavior. macOS 27 resolves hostnames like albert.apple.com (device activation, certificate-pinned), push messaging hosts, and ipv4only.arpa for NAT64 networks. The OS still uses a TCP window scale of 6, ECN, and random timestamps, with only four TCP connections observed during boot. The analysis provides a reference baseline for security teams monitoring Apple endpoints.

SANS Internet Storm Center · 1d agoResearch

Plug 'n' Pray: Agentic LLM-based Detection of Potential Log File Exposures in Third-Party Content Management System Plugins

Agentic LLM analysis validates 79 log file exposures across 62 of the 300 most-installed WordPress plugins, covering 250M+ active installations.

Researchers built an agentic LLM-based framework combining static and dynamic analysis to automatically detect insecure log files created by WordPress plugins. Scanning the 300 most-installed plugins, which account for roughly 75% of all active installations in the official ecosystem, it produced 81 findings with 79 manually reproduced across 62 plugins. Insufficiently secured log files can disclose credentials and personal data and have led to website compromises. The authors derive a taxonomy of log path and protection patterns and best practices, finding multi-layered protection often absent.

arXiv cs.CR · 1d agoResearch

GDCM <= 3.2.7: six memory-safety and denial-of-service vulnerabilities, no CVE

Six memory-safety and denial-of-service flaws disclosed in the GDCM DICOM parsing library, affecting versions through 3.2.7.

Researcher Abhinav Agarwal disclosed six vulnerabilities in GDCM (Grassroots DICOM), an open-source C++ library for parsing and processing DICOM files. All six were confirmed against GDCM 3.2.6 using AddressSanitizer and UndefinedBehaviorSanitizer, and source review found the vulnerable patterns through version 3.2.7 and the upstream master snapshot. Potential impacts include heap corruption, process-memory disclosure, stack exhaustion, and process termination in applications parsing untrusted DICOM files. No CVE identifiers have been assigned at the time of disclosure.

oss-security · 7d agoVulnerability

CVE-2026-89775: Guest-to-Host Escape in KVM/arm64

Disclosed CVE-2026-89775 lets a guest VM escape to the host on KVM/arm64 systems with nested virtualization enabled.

Researcher Hyunwoo Kim disclosed CVE-2026-89775, a guest-to-host escape in KVM/arm64, after the embargo agreed with linux-distros maintainers expired. The root cause is a type truncation of the stage-1 walk level that makes a size computation return 0, the value meaning 'size unknown'. The VNCR pseudo-TLB invalidation path then interprets that 0 as a valid value on ARM64 hosts where nested virtualization is enabled.

oss-security · 12h agoVulnerabilityCVE-2026-89775

ZDI-26-710: NoMachine mDNS Heap-based Buffer Overflow Remote Code Execution Vulnerability

ZDI disclosed CVE-2026-92208, an unauthenticated heap-based buffer overflow in NoMachine's mDNS service enabling network-adjacent remote code execution (CVSS 8.8).

ZDI published advisory ZDI-26-710 describing a heap-based buffer overflow vulnerability in NoMachine's mDNS service, tracked as CVE-2026-92208 with CVSS 8.8. Network-adjacent attackers can execute arbitrary code on affected installations without authentication. The advisory does not mention observed exploitation or patch availability.

CVE-2026-67211: Apache OpenNLP: OOM DoS via Unbounded Array Allocation in SymSpellModelSerializer

Apache OpenNLP CVE-2026-67211: unbounded map pre-sizing in SymSpellModelSerializer enables out-of-memory denial of service in opennlp-symspell 3.0.0-M4/M5.

CVE-2026-67211 affects the opennlp-symspell artifact in versions 3.0.0-M4 and 3.0.0-M5 only. The SymSpellModelSerializer.create() method performs unbounded map pre-sizing, allowing crafted input to trigger out-of-memory denial of service. Releases 1.x and 2.x are unaffected because the spellcheck extension was introduced in 3.0.0-M4; the issue is resolved in 3.0.0-M6.

Graph Machine: Towards Better Pretraining via Edges

Researchers propose Graph Machine, an O(n)-state sparse architecture that replaces 75% of Qwen3-0.6B dense layers with only slight loss change.

The paper introduces the Graph Machine (GM), an architecture that maintains an O(n)-sized state accessed through sparse, dynamic routing via pointer-like edges updated differentiably by a referral mechanism resembling pointer chasing. The authors replaced 75% of dense Transformer layers in Qwen3-0.6B with GM sparse layers and pretrained from scratch on 15.7B tokens. Retrieving 2 of 4,096 tokens per KV head in each sparse layer degrades loss only slightly, while retrieving 4 marginally improves loss over the dense baseline.

Hugging Face daily papers · 15d agoAI research

FrostyGoop’s Zoom-In: A Closer Look into the Malware Artifacts, Behaviors and Network Communications

Unit 42 dissects FrostyGoop OT malware, which sent Modbus TCP commands to disrupt heating for 600+ apartment buildings in Ukraine.

Palo Alto Unit 42 analyzed new FrostyGoop/BUSTLEBERM samples, the ninth known ICS-centric malware, first used against a Ukrainian municipal energy company by sending Modbus TCP commands to ENCO control devices. The attack caused a two-day heating outage affecting over 600 apartment buildings during sub-zero temperatures. The Go-compiled malware accepts Modbus register operations and timing parameters via command-line arguments or a JSON configuration file, uses an obscure open-source Modbus library, and checks the Windows BeingDebugged flag to evade debuggers. Unit 42 telemetry recorded over 1 million Modbus TCP devices exposed to the internet between September and October 2024.

Palo Alto Unit 42 · 28d agoMalware in the wild

Almost Half of Malware Samples Communicate Direct to IP

Unit 42 analysis of 4 million malware reports finds 45% of C2-active samples connect directly to hard-coded IPs, bypassing DNS defenses.

Palo Alto Unit 42 analyzed over 4 million Advanced WildFire dynamic analysis reports and found that 45.32% of malware samples with C2 activity made at least one direct-to-IP connection, accounting for 23.17% of all C2 connection attempts. The firm proposes zero trust IP (ZT-IP), an enforcement approach that verifies whether outbound destinations were ever sanctioned by a DNS response. ZT-IP analysis surfaced Phorpiex ransomware droppers fetching payloads directly from C2 IPs, a persistent data exfiltration campaign using an obfuscated \GET protocol, and Mozi P2P botnet payloads delivered to IoT devices without DNS. Only 1% of benign samples connected directly to untrusted IP addresses.

Palo Alto Unit 42 · Aug 17, 2026Research

USN-8772-1: AOM vulnerabilities

Ubuntu USN-8772-1 patches four libaom flaws (CVE-2026-56208 to CVE-2026-56211) that could cause heap overflow, arbitrary memory writes, or code execution.

Ubuntu Security Notice USN-8772-1 fixes a heap buffer overflow in libaom's first-pass statistics buffer handling in Look-Ahead Processing mode (CVE-2026-56208), potentially causing denial of service or arbitrary code execution. Three additional flaws in spatial and temporal layer ID validation in the SVC encoder controls (CVE-2026-56209, CVE-2026-56210, CVE-2026-56211) allow arbitrary memory writes, out-of-bounds heap reads, or code execution. Users should apply the updated packages.

openbmb/MiniCPM5-2B-GGUF — new model trending #30 on Hugging Face

OpenBMB released MiniCPM5-2B, a dense 2B on-device model claiming open-source SOTA among 2B-class models.

OpenBMB released MiniCPM5-2B, the second model in the MiniCPM5 series following MiniCPM5-1B, as a dense 2B Transformer built for on-device and resource-constrained deployment with GGUF weights on Hugging Face. The team claims 2B-class open-source state-of-the-art performance, remaining competitive with 4B-class models in coding, mathematics, long-context understanding, tool use and agentic tasks. The release includes a tech report, GitHub repository and online demo, and is currently trending on Hugging Face.

Hugging Face trending models · 12d agoModel release2

Scans Targeting Hospitality Applications, (Wed, Sep 16th)

Scans from a bulletproof-hosting IP target the abandoned PIAF-HMS hospitality application, which contains numerous unpatched SQL injection flaws.

SANS ISC observed requests for /PIAF-HMS/ using the unusual user-agent Farez-Sorter/1.0, along with paths like /admin/, /ucp/, /hms/, and /hotel/, starting September 15 from the single source IP 94.102.49.125 (IP Volume, AS202425, a bulletproof hoster). PIAF-HMS, a PBX in a Flash Hospitality Management System, was last updated 10 years ago and a SQL injection vulnerability was reported recently; the code shows many injection flaws and lacks authentication and access control. The handler notes hotels are soft targets for personal data theft and guest MitM attacks, and asks for community insight on the campaign.

SANS Internet Storm Center · 10h agoExploit / PoC