Critical Remote Code Execution and Authorization Bypass Vulnerabilities in Cisco ASA and FTD WebVPN
Multiple critical vulnerabilities have been discovered in the Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) WebVPN components, which are being actively exploited in the wild. The vulnerabilities, identified as CVE-2025-20362, CVE-2025-20333, and CVE-2025-20363, allow attackers to bypass authentication and achieve remote code execution (RCE) as root on affected devices. CVE-2025-20362 is an unauthenticated authorization bypass that enables attackers to access restricted endpoints without valid credentials, serving as a key component in exploit chains. When combined with CVE-2025-20333, attackers can send malicious HTTPS requests to execute arbitrary code as root, even without prior authentication. CVE-2025-20363 is a related flaw that also enables unauthenticated RCE on ASA/FTD devices and authenticated RCE on some Cisco IOS components. These vulnerabilities affect Cisco ASA versions 9.16 through 9.23 and Cisco FTD versions 7.0 through 7.7, with specific software images requiring validation against Cisco advisories. Cisco and CISA have confirmed active exploitation and widespread scanning for these vulnerabilities, prompting CISA to issue Emergency Directive 25-03 on September 25, 2025, mandating immediate action by federal agencies. The threat actor responsible for these attacks is attributed to the same group behind the ArcaneDoor (UAT4356) state-sponsored espionage campaign first observed in 2024. Organizations are urged to patch or upgrade to Cisco’s fixed releases without delay, and to restrict or disable vulnerable devices if immediate upgrades are not possible. Compromised devices should be isolated and thoroughly investigated for signs of threat actor presence. Cisco has provided detailed guidance for detection, and CISA’s Malware Next Generation tool can be used to hunt for indicators of compromise. Security researchers, including Rapid7, have published technical analyses and exploit chains demonstrating the severity and ease of exploitation. The vulnerabilities are considered highly critical due to their unauthenticated nature and the potential for full device compromise, which could lead to further lateral movement within affected networks. The rapid response from both Cisco and CISA underscores the urgency and scale of the threat. Organizations using Cisco ASA or FTD devices should assume exposure if running affected versions and prioritize remediation. The vulnerabilities highlight the ongoing targeting of network edge devices by sophisticated threat actors, particularly those engaged in espionage. Failure to address these vulnerabilities could result in significant operational disruption and data compromise. The security community continues to monitor for new exploitation techniques and advises ongoing vigilance. The release of proof-of-concept code and active scanning increases the risk of opportunistic attacks by additional threat actors. Timely patching and adherence to Cisco and CISA recommendations are essential to mitigate risk from these critical vulnerabilities.
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How this story unfolded
3 events from the most recent confirmed update back to the earliest known activity.
Horizon3.ai releases technical research on Cisco ASA/FTD WebVPN flaws
Horizon3.ai published additional technical research covering CVE-2025-20362, CVE-2025-20333, and CVE-2025-20363 in Cisco ASA/FTD WebVPN. The write-up provided further public detail on the vulnerabilities and their security implications.
Rapid7 publishes analysis of Cisco ASA zero-day exploit chain
Rapid7 detailed an exploit chain involving Cisco ASA vulnerabilities CVE-2025-20362 and CVE-2025-20333, describing how the bugs could be combined in real-world attacks. This public technical analysis expanded understanding of the attack path and exploitation risk.
Cisco discloses ASA/FTD WebVPN vulnerabilities and fixes
Cisco disclosed multiple vulnerabilities affecting ASA and FTD WebVPN, including CVE-2025-20362, CVE-2025-20333, and CVE-2025-20363, and released security updates to address them. The reporting indicates the issues were significant enough to be treated as actively relevant security flaws, including a zero-day exploit chain involving ASA.
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Exploitation of Cisco ASA and FTD Zero-Day Vulnerabilities by Storm-1849
Cisco confirmed that attackers have been actively exploiting two zero-day vulnerabilities, CVE-2025-20333 and CVE-2025-20362, in Cisco Secure Firewall Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) software. These vulnerabilities allow attackers to execute arbitrary code as root and access restricted URLs without authentication, leading to device reloads and denial-of-service (DoS) conditions. The U.K. National Cyber Security Centre (NCSC) and Cisco have linked these exploits to malware campaigns involving RayInitiator and LINE VIPER, and have urged immediate patching. Security advisories highlight that unpatched devices are at risk of persistent compromise, and recommend comprehensive remediation steps including patching, forensic analysis, and resetting credentials. Threat intelligence reports attribute the exploitation campaign to the China-linked group Storm-1849 (ArcaneDoor), which targeted U.S. financial institutions, defense contractors, and military organizations throughout October. Despite public disclosure and patch directives from CISA, attacks continued, demonstrating the attackers' operational sophistication and persistence. Experts warn that organizations running unpatched ASA devices should assume compromise and prioritize forensic hunting for ROM-level malware, as well as implement robust monitoring and maintenance practices to mitigate ongoing risks.
Apr 25, 2026
Coordinated Attacks and Zero-Day Exploitation Targeting Cisco, Palo Alto, and Fortinet Network Devices
A coordinated cyberattack campaign has been identified targeting major networking devices from Cisco, Palo Alto Networks, and Fortinet, with evidence suggesting a single threat actor is orchestrating the activity. Security researchers at GreyNoise observed simultaneous scanning of Cisco ASA devices, increased login attempts against Palo Alto Networks portals, and brute-force attacks on Fortinet SSL VPNs, all originating from shared subnets and exhibiting recurring TCP fingerprints. This temporal and infrastructural correlation points to a sophisticated, cross-vendor campaign rather than opportunistic attacks. Experts note that adversaries are leveraging generative AI to automate these attacks, adopting tactics typically associated with nation-state actors. The campaign is notable for its focus on high-value targets such as networking devices and VPNs, which serve as critical gateways into enterprise networks and often possess privileged access that can bypass internal security controls. Industries such as manufacturing, industrials, and utilities are particularly at risk due to the potential for operational disruption and rapid financial gain for attackers. Concurrently, Cisco disclosed two zero-day vulnerabilities in its ASA and Secure Firewall Threat Defense software, identified as CVE-2025-20333 and CVE-2025-20362, which are being actively exploited in the wild. CVE-2025-20333 allows authenticated remote code execution due to improper input validation in the VPN web server, potentially granting attackers root-level access. CVE-2025-20362 is an authentication bypass flaw that enables remote attackers to access restricted endpoints without credentials. The combination of these vulnerabilities poses a severe risk, as attackers can gain full control of affected devices. Cisco’s Product Security Incident Response Team (PSIRT) has confirmed ongoing exploitation and is collaborating with government agencies to coordinate a response. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has issued an emergency directive, urging all federal agencies to immediately mitigate exposure and assess for compromise. Over 90,000 Cisco FTD devices are reportedly exposed, highlighting the scale of the threat. Attackers are conducting large-scale scanning campaigns to identify vulnerable ASA login portals and entry points. Security experts emphasize the urgent need for organizations to inventory their Cisco ASA and FTD devices, apply available patches, and implement recommended mitigations. The campaign’s use of shared infrastructure and advanced automation underscores a shift in attacker methodology toward more efficient and targeted operations. The strategic targeting of network infrastructure devices reflects their critical role in enterprise security and the high impact of successful compromise. Organizations are advised to monitor for signs of compromise, follow vendor and government guidance, and prioritize remediation of affected systems. The ongoing nature of the attacks and the active exploitation of zero-day vulnerabilities make this a critical threat to enterprise and government networks worldwide.
Mar 21, 2026
Critical Zero-Day Exploitation of Cisco Security Appliances
Multiple critical zero-day vulnerabilities have been exploited in Cisco security products, targeting both email security appliances and network firewalls. A China-linked APT, identified as UAT-9686, exploited a zero-day vulnerability (CVE-2025-20393) in Cisco email security appliances running AsyncOS, specifically when the Spam Quarantine feature is internet-accessible. This flaw allows attackers to gain root privileges, posing a severe risk to organizations relying on these appliances for email protection. In parallel, Cisco Secure Firewall Adaptive Security Appliance (ASA) and Threat Defense (FTD) software have been targeted by a separate espionage campaign, linked to the ArcaneDoor threat actor, exploiting multiple zero-days (CVE-2025-20333, CVE-2025-20362, CVE-2025-20363) to achieve unauthenticated remote code execution and persistent access, even after system reboots or upgrades. These campaigns have prompted emergency directives from CISA and highlight the ongoing threat to perimeter network devices. Attackers have leveraged these vulnerabilities to establish persistent footholds, manipulate device memory, and potentially pivot deeper into victim networks. The vulnerabilities affecting ASA and FTD firewalls were publicly disclosed and patched, but the email security appliance zero-day remains unpatched, increasing the urgency for organizations to review their exposure and apply mitigations where possible.
Mar 21, 2026