AI-powered attacks target Siemens PLCs in active campaign

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NSA, CISA, FBI, DOE, and EPA issued joint advisory AA26-231A warning of active attacks on Siemens S7 PLCs. Threat actors are using AI-generated Python exploits to target S7-200 through S7-1500 controllers exposed on TCP port 102. The campaign affects Energy, Water, Manufacturing, Chemical, Food/Agriculture, and Commercial Facilities sectors. Federal agencies cite active reconnaissance and capability development, not theoretical risk.

This week also brought a 533× improvement in Linux 7.3 memory lock performance and Cloudflare's demonstration of a 12 bit/s Spectre attack in production Workers.

In this issue:

• Active Siemens S7 PLC exploitation using AI-generated scripts
• Linux 7.3 per-memcg LRU locks: 533× faster under contention
• Cloudflare Spectre research: 12 bit/s leak in production serverless
• NAND revenue up 77% as AI server demand drives supply shortage

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Active Attacks on Siemens PLCs Using AI-Generated Exploits

The Signal

NSA, CISA, FBI, DOE, and EPA issued joint advisory AA26-231A warning of active exploitation targeting Siemens S7 Series PLCs.

What Changed

• Threat actors use AI-generated Python scripts with `snap7.dll` library to exploit S7-200, S7-300, S7-400, S7-1200, and S7-1500 controllers.
• Attackers scan for Internet-exposed PLCs on TCP port 102 using Censys and ZoomEye services.
• Exploits disguised as monitoring tools target outdated firmware and default credentials in critical infrastructure sectors.
• Campaign affects Energy, Water, Manufacturing, Chemical, Food/Agriculture, and Commercial Facilities sectors per CISA advisory AA26-231A.
• Federal agencies cite active reconnaissance and capability development, not theoretical risk.

Operational Impact

Teams running Siemens S7 PLCs must inventory all controllers immediately and verify none are Internet-accessible. Block TCP port 102 at perimeter firewalls, apply latest firmware patches, and enable password protection with write/read protection levels on all devices. Organizations relying on third-party integrators or MSPs should confirm those partners have implemented network isolation and access controls, as asset owners may not know systems are exposed. Deploy ICS-aware monitoring to detect unauthorized S7comm connections and alert on PUT/GET operations outside maintenance windows.

Watch For

AI-assisted exploit generation lowers technical barriers for ICS attacks across all PLC vendors. Multi-agency involvement and sector-specific warnings suggest intelligence indicating pre-positioning for disruptive operations.

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Linux 7.3 Memory Management: 533× Faster LRU Locks

The Signal

Linux 7.3 merges per-memcg LRU locks, cutting lock hold time from 8ms to 15μs under contention.

What Changed

• Per-memory-cgroup LRU locking replaces global lruvec locks in Linux 7.3 MM subsystem.
• Worst-case anon_vma lock hold time drops from 705ms to 1.67ms in KSM reverse mapping.
• Benefits workloads with 20,000+ VMAs sharing single anon_vma (common in JVM, Go runtimes).
• Batched page table zapping defers TLB flushes, improving `munmap()` performance significantly.
• ZTE measured 533× improvement in lock contention scenarios on high-core-count servers.

Operational Impact

Teams running high-density container platforms will see reduced tail latency under memory pressure. Applications that split VMAs via `mprotect()` or `madvise()` (Java heaps, PostgreSQL shared buffers) previously froze for hundreds of milliseconds during page faults or compaction. The new per-cgroup lock architecture eliminates blocking across unrelated memory operations, directly improving throughput and preventing container timeouts.

Watch For

Profile anon_vma lock hold times if you run KSM on production systems. The optimization is most visible when VMA counts exceed several thousand per anon_vma.

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Cloudflare Demonstrates Production Spectre Attack at 12 bit/s

The Signal

Cloudflare security team achieved 12 bit/s information leak with 99% accuracy using Spectre in production Workers environment.

What Changed

• Research applied newer stabilization techniques from VUSec's portable Spectre work to multi-tenant serverless platform.
• Attack bypassed Dynamic Process Isolation (DyPrIs) using Durable Objects for multi-hour isolate persistence.
• Team demonstrated cross-isolate heap read via speculative type confusion and 64-bit pointer leakage.
• Mitigations now deployed: V8 Sandbox integration, Memory Protection Keys (MPK) for in-process isolation, improved DyPrIs detection.
• Full paper published with University of Edinburgh researchers covering 2024-2025 work: https://blog.cloudflare.com/revisiting-spectre-attacks-on-workers

Operational Impact

Teams running multi-tenant JavaScript runtimes or serverless platforms should reassess Spectre risk models. Academic techniques like tree-based PLRU cache amplification and remote WebSocket timers enable practical attacks despite coarse-grained timers and process isolation. The V8 Sandbox removes raw 64-bit pointers from heap structures but doesn't eliminate all Spectre gadgets. MPK-based in-process isolation adds hardware-enforced access boundaries between tenant heaps within shared processes.

Watch For

Cloudflare is investigating remote timing patterns as detection signal for DyPrIs. No evidence of exploitation found in three years of production logs.

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NAND Revenue Surges 77% on AI Server Demand

The Signal

Top five NAND vendors reported $68.87B combined revenue in Q2 2026, up 77% quarter-over-quarter.

What Changed

• AI server demand for enterprise SSDs drove sustained ASP increases through contract negotiations.
• Samsung held 29.3% share; Micron moved to third at 15.1% share.
• Vendors prioritizing capex for DRAM and HBM, limiting new NAND flash capacity expansion.
• Supply shortage expected to continue through Q3 2026, supporting further ASP growth.

Operational Impact

Teams procuring storage should budget for continued ASP increases through at least Q3. Vendors are deliberately constraining NAND capacity to prioritize DRAM/HBM production for AI workloads. Enterprise SSD procurement timelines may extend as supply tightness persists.

Watch For

Monitor whether vendors announce NAND capacity expansion in 2H 2026. BNP Paribas notes inference workloads require tiered memory including NAND, sustaining demand independent of HBM allocation decisions.

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Quick Reads

• Siemens PLCs — AI-generated exploits actively target S7 controllers exposed on TCP port 102.
• Linux 7.3 — New per-cgroup LRU locks cut memory contention from 8ms to 15μs.
• Cloudflare Workers — Research team achieved 12 bit/s Spectre leak in production serverless environment.
• NAND Flash — Q2 revenue jumped 77% to $68.87B on AI server SSD demand.