Identity Services Engine CVE-2025-20282

This vulnerability presents exceptionally high real-world risk across multiple threat intelligence dimensions. CVSS 3.1 vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H) indicates: Network-accessible attack vector, Low complexity, No privileges required, No user interaction, and scope changes with Complete confidentiality/integrity/availability impact—textbook critical RCE. The perfect CVSS score (10.0) aligns with real exploitability: unauthenticated network access, no technical barriers, and complete OS compromise. This CVE likely has HIGH EPSS probability given the simplicity of exploitation (file upload + execution) and broad applicability. If present in CISA KEV or noted as actively exploited, this becomes an immediate threat requiring emergency patching. The attack surface is large—any organization deploying Cisco ISE for network access control, 802.1X authentication, or endpoint compliance faces exposure. Unlike theoretical high-CVSS issues, this combines ease of exploitation (AC:L), accessibility (AV:N, PR:N), and catastrophic impact (complete system compromise), making it a genuine critical priority rather than scoring inflation.

Attacker reconnaissance: Security researcher or threat actor identifies ISE internal API endpoint via port scanning (typically ISE admin port 443, or internal API ports 8080, 8081) or public documentation. Exploitation: Attacker crafts HTTP POST request to the vulnerable file upload endpoint (path varies, e.g., /admin/api/upload or similar internal API path) with Content-Type: multipart/form-data containing a malicious payload. The payload could be: (1) Bash script in /usr/local/bin with execution bit, (2) Binary compiled for target ISE Linux variant (CentOS, RHEL-based), (3) Python script placed in cron.daily or cron.hourly directories, (4) Reverse shell connecting to attacker C2. Request example: POST /internal/api/files/upload HTTP/1.1, no authentication headers required. Server accepts file, fails to validate path, stores in /usr/bin/malicious_script.sh due to path injection or missing validation. Attacker then triggers execution: either via subsequent API call, cron job, or direct SSH access to execute the file as root. Impact: Full ISE compromise—attacker gains root shell, modifies ISE configuration, exfiltrates network credentials from ISE database, modifies authentication policies to grant access to internal network resources, or establishes persistent backdoor. Network impact cascades: if ISE controls 802.1X or network access, attacker can pivot to connected endpoints, bypass MFA, or launch supply-chain attacks on dependent systems.