securityaffairs.com
October 04, 2025
Pierluigi Paganini

GreyNoise saw a 500% spike in scans on Palo Alto Networks login portals on Oct. 3, 2025, the highest in three months.
Cybersecurity firm GreyNoise reported a 500% surge in scans targeting Palo Alto Networks login portals on October 3, 2025, marking the highest activity in three months.

On October 3, the researchers observed that over 1,285 IPs scanned Palo Alto portals, up from a usual 200. The experts reported that 93% of the IPs were suspicious, 7% malicious.
Most originated from the U.S., with smaller clusters in the U.K., Netherlands, Canada, and Russia.

GryNoise defined the traffic targeted and structured, aimed at Palo Alto login portals and split across distinct scanning clusters.

The scans targeted emulated Palo Alto profiles, focusing mainly on U.S. and Pakistan systems, indicating coordinated, targeted reconnaissance.

GreyNoise found that recent Palo Alto scanning mirrors Cisco ASA activity, showing regional clustering and shared TLS fingerprints linked to the Netherlands infrastructure. Both used similar tools, suggesting possible shared infrastructure or operators. The overlap follows a Cisco ASA scanning surge preceding the disclosure of two zero-day vulnerabilities.

“Both Cisco ASA and Palo Alto login scanning traffic in the past 48 hours share a dominant TLS fingerprint tied to infrastructure in the Netherlands. This comes after GreyNoise initially reported an ASA scanning surge before Cisco’s disclosure of two ASA zero-days.” reads the report published by Grey Noise. “In addition to a possible connection to ongoing Cisco ASA scanning, GreyNoise identified concurrent surges across remote access services. While suspicious, we are unsure if this activity is related. “

GreyNoise noted in July spikes in Palo Alto scans sometimes preceded new flaws within six weeks; The experts are monitoring if the latest surge signals another disclosure.
“GreyNoise is developing an enhanced dynamic IP blocklist to help defenders take faster action on emerging threats.” concludes the report.

GreyNoise has observed a significant surge in login scanning activity targeting Palo Alto Networks PAN-OS GlobalProtect portals. Over the last 30 days, nearly 24,000 unique IP addresses have attempted to access these portals. The pattern suggests a coordinated effort to probe network defenses and identify exposed or vulnerable systems, potentially as a precursor to targeted exploitation.

Recent patterns observed by GreyNoise suggest that this activity may signal the emergence of new vulnerabilities in the near future:

“Over the past 18 to 24 months, we’ve observed a consistent pattern of deliberate targeting of older vulnerabilities or well-worn attack and reconnaissance attempts against specific technologies,” said Bob Rudis, VP of Data Science at GreyNoise. “These patterns often coincide with new vulnerabilities emerging 2 to 4 weeks later.”

The recently disclosed Palo Alto Networks firewall vulnerability tracked as CVE-2024-3400, which has been exploited in attacks for at least one month, has been found to impact one of Siemens’ industrial products.

In an advisory published late last week, Siemens revealed that its Ruggedcom APE1808 devices configured with a Palo Alto Networks virtual next-generation firewall (NGFW) could be affected by CVE-2024-3400.