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FIRESTARTER Backdoor

KEV CRITICAL Cisco FIRESTARTER CVE-2025-20333 CVE-2025-20362 Cisco Firepower

Strategische Zusammenfassung

FIRESTARTER backdoor provides persistent access on Cisco ASA/FTD devices, enabling long-term espionage and lateral movement.

Relevanz für dich

FIRESTARTER backdoor provides persistent access on Cisco ASA/FTD devices, enabling long-term espionage and lateral movement.

Volltext

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| Malware Name | FIRESTARTER | | --- | | Original Publication | April 23, 2026 | | Executive Summary | The Cybersecurity and Infrastructure Security Agency (CISA) analyzed a sample of FIRESTARTER malware obtained from a forensic investigation. CISA and the United Kingdom National Cyber Security Centre (NCSC) assess advanced persistent threat (APT) actors are using FIRESTARTER malware for persistence, specifically targeting publicly accessible Cisco Firepower and Secure Firewall devices running Adaptive Security Appliance (ASA) or Firepower Threat Defense (FTD) software. CISA and the NCSC are releasing this Malware Analysis Report to share analysis of one FIRESTARTER malware sample operating as a backdoor and urge organizations to take key response actions. **Note:** The release of this Malware Analysis Report aligns with CISA’s update to V1: Emergency Directive (ED) 25-03: Identify and Mitigate Potential Compromise of Cisco Devices and Supplemental Direction ED 25-03: Core Dump and Hunt Instructions. The malware outlined in this report is relevant for both Cisco Firepower and Secure Firewall devices; however, CISA has only observed a successful implant of the malware in the wild on a Cisco Firepower device running ASA software. | | Key Actions for U.S. FCEB Agencies | * **Collect and submit core dumps** to CISA’s Malware Next Generation platform. * **Immediately report the submission** via CISA’s 24/7 Operations Center; CISA will reach out with next steps. * **Take no additional action until CISA provides further guidance.** | | Key Actions for All Other Organizations | * **Use the YARA rules** to detect FIRESTARTER malware against either a disk image or core dump of a device. * **Report any findings to CISA or the NCSC.** * **If compromise is confirmed**, conduct incident response actions. | | Intended Audience | **Organizations:** Government and critical infrastructure organizations (**Note:** While this publication supplements CISA ED 25-03, the guidance is applicable to all organizations, including U.K.

  • Maintain all systems and software with the latest security patches, prioritizing expedited remediation of vulnerabilities

CISA Central[1-844-Say-CISA](tel:1-844-Say-CISA)[[email protected]](mailto:[email protected])

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Erwähnte CVEs

Risk Score

100
cvss base
99.00
kev bonus
20.00
epss bonus
0.00
poc bonus
15.00
raw before weight
134.00
industry weight
1.56
freshness factor
1.00
days old
0.00

Pfad: operational

MITRE ATT&CK Mapping

5 TTPs
Recon
Resource Dev
Priv. Escal.
Cred. Access
Discovery
Lateral Mov.
Collection
C2
Exfiltration
Impact
Conf.: high medium low

Procedure-Details

Technik Tactic Procedure Conf. Quelle
T1190
Exploit Public-Facing Application
Initial Access APT actors exploit CVE-2025-20333 and CVE-2025-20362 in publicly accessible Cisco Firepower and Secure Firewall devices running ASA or FTD software to gain initial access and deploy FIRESTARTER malware high llm
T1542.004
ROMMONkit
Defense Evasion FIRESTARTER operates as a backdoor on Cisco Firepower and Secure Firewall network devices, implanting itself to persist within the device firmware/software stack outside of traditional OS-level visibility medium llm
T1505.001
SQL Stored Procedures
Persistence FIRESTARTER malware is specifically used for persistence on compromised Cisco Firepower and Secure Firewall devices running ASA or FTD software, maintaining access as a backdoor across reboots high llm
T1133
External Remote Services
Persistence FIRESTARTER backdoor targets publicly accessible Cisco Firepower and Secure Firewall devices, which serve as external remote access infrastructure, allowing APT actors to maintain persistent remote access to victim networks high llm
T1059
Command and Scripting Interpreter
Execution FIRESTARTER operates as a backdoor on Cisco network devices, enabling APT actors to execute commands on compromised Cisco Firepower and Secure Firewall appliances running ASA or FTD software medium llm
ESC