Cyber intelligence firm GreyNoise has uncovered what appears to be a coordinated exploitation effort targeting network edge appliances from three major security vendors: Cisco, Fortinet, and Palo Alto Networks. After analyzing overlapping IP subnets, identical TCP fingerprints, and synchronized attack patterns, GreyNoise assessed with high confidence that these separate waves of scanning and brute-force attacks are linked to the same threat actor or group.

The report connects this activity to three ongoing campaigns:

• Cisco ASA and FTD Exploitation: Early September scans occurred weeks before Cisco disclosed two zero-day flaws later tied to the ArcaneDoor espionage campaign, signaling an adversary with privileged vulnerability knowledge.
• Palo Alto Networks GlobalProtect Attacks: A 500% surge in scanning and 1.3 million login attempts targeted firewall portals within a single week, hinting at large-scale credential harvesting efforts.
• Fortinet VPN Brute-Forcing: Persistent login attacks correlated with predictive vulnerability cycles, often preceding new Fortinet flaw disclosures by about six weeks.

Together, these findings suggest a well-resourced actor conducting synchronized operations to map, exploit, and potentially pre-position within global enterprise networks. The intelligence also offers a crucial defensive takeaway: spikes in brute-force or scanning activity may serve as early warnings of vulnerabilities soon to be revealed.

In this episode, we break down how GreyNoise linked these campaigns, why this activity may represent the next evolution of state-linked cyber espionage, and how organizations can use predictive threat signals to move from reactive defense to proactive mitigation.

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