Grey Noise

GreyNoise has observed active exploitation attempts against CVE-2025-5777 (CitrixBleed 2), a memory overread vulnerability in Citrix NetScaler. Exploitation began on June 23 — nearly two weeks before a public proof-of-concept was released on July 4. 

GreyNoise has identified a previously untracked variant of a scraper botnet, detectable through a globally unique network fingerprint. To detect it, GreyNoise analysts created a signature using JA4+, the suite of JA4 signatures used to fingerprint network traffic.

GreyNoise has identified a notable surge in scanning activity targeting MOVEit Transfer systems, beginning on May 27, 2025. Prior to this date, scanning was minimal — typically fewer than 10 IPs observed per day. But on May 27, that number spiked to over 100 unique IPs, followed by 319 IPs on May 29. 

‍On June 16, GreyNoise observed exploit attempts targeting CVE-2023-28771 — a remote code execution vulnerability affecting Zyxel Internet Key Exchange (IKE) packet decoders over UDP port 500.

GreyNoise recently observed a coordinated spike in malicious activity against Apache Tomcat Manager interfaces. On June 5, 2025, two GreyNoise tags — Tomcat Manager Brute Force Attempt and Tomcat Manager Login Attempt — registered well above baseline volumes, indicating a deliberate attempt to identify and access exposed Tomcat services at scale.

GreyNoise uncovers a stealth campaign exploiting ASUS routers, enabling persistent backdoor access via CVE-2023-39780 and unpatched techniques. Learn how attackers evade detection, how GreyNoise discovered it with AI-powered tooling, and what defenders need to know.

On May 8, GreyNoise observed a highly coordinated reconnaissance campaign launched by 251 malicious IP addresses, all geolocated to Japan and hosted by Amazon AWS. The infrastructure and execution suggest centralized planning.

Two critical Ivanti zero-days (CVE-2025-4427 and CVE-2025-4428) are now being actively exploited after a surge in scanning activity last month. When chained together, these vulnerabilities enable unauthenticated remote code execution on Ivanti Endpoint Manager Mobile systems.

Edge vulnerabilities are a critical and growing threat. The 2025 DBIR reveals an eightfold surge in exploitation, yet many remain unpatched despite immediate risk.

GreyNoise observed a significant increase in crawling activity targeting Git configuration files. While the crawling itself is reconnaissance, successful discovery of exposed Git configuration files can lead to exposure of internal codebases, developer workflows, and potentially sensitive credentials.

GreyNoise observed a 9X spike in suspicious scanning activity targeting Ivanti Connect Secure or Ivanti Pulse Secure VPN systems. More than 230 unique IPs probed ICS/IPS endpoints. This surge may indicate coordinated reconnaissance and possible preparation for future exploitation. 

Attackers from every corner of the internet are exploiting a uniquely dangerous class of cyber flaws: resurgent vulnerabilities. GreyNoise’s latest research breaks down these vulnerabilities — how they behave, why they’re dangerous, and what defenders and policymakers need to know to stay ahead.

GreyNoise has observed a significant spike in exploitation attempts against TVT NVMS9000 DVRs. This information disclosure vulnerability can be used to gain administrative control over affected systems. 

On March 28, GreyNoise observed a significant spike in activity targeting multiple edge technologies, including SonicWall, Zoho, Zyxel, F5, Linksys, and Ivanti systems. While some of these technologies are edge systems, others are primarily internal management tools. 

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. 

GreyNoise is bringing awareness to in-the-wild activity against several known vulnerabilities (CVE-2020-8515, CVE-2021-20123, and CVE-2021-20124) in DrayTek devices.

Attackers are actively exploiting Apache Tomcat servers by leveraging CVE-2025-24813, a newly disclosed vulnerability that, if successfully exploited, could enable remote code execution (RCE). GreyNoise has identified multiple IPs engaging in this activity across multiple regions. 

GreyNoise has identified a notable resurgence of in-the-wild activity targeting three ServiceNow vulnerabilities: "Resurgence of in-the-wild Activity targeting critical ServiceNow vulns. Overwhelming majority of traffic hitting Israel.

GreyNoise observed 400+ IPs exploiting multiple SSRF vulnerabilities across various platforms, with recent activity concentrated in Israel and the Netherlands.

‍GreyNoise data confirms that exploitation of CVE-2024-4577 extends far beyond initial reports. Attack attempts have been observed across multiple regions, with notable spikes in the United States, Singapore, Japan, and other countries throughout January 2025.