By Bill Toulas
Publication Date: 2025-11-12 14:00:00
An advanced threat actor exploited the critical vulnerabilities “Citrix Bleed 2″ (CVE-2025-5777) in NetScaler ADC and Gateway, and CVE-2025-20337 affecting Cisco Identity Service Engine (ISE) as zero-days to deploy custom malware.
Amazon’s threat intelligence team, analyzing “MadPot” honeypot data, found that hackers leveraged the two security issues before the security issues were disclosed publicly and patches became available.
“Our Amazon MadPot honeypot service detected exploitation attempts for the Citrix Bleed Two vulnerability (CVE-2025-5777) prior to public disclosure, indicating a threat actor had been exploiting the vulnerability as a zero-day,” explains Amazon.
“Through further investigation of the same threat exploiting the Citrix vulnerability, Amazon Threat Intelligence identified and shared with Cisco an anomalous payload targeting a previously undocumented endpoint in Cisco ISE that used vulnerable deserialization…
