CVE-2015-6420
CRITICALCVE-2015-6420 is a critical-severity (CVSS 9.8) Deserialization of Untrusted Data vulnerability in apache commons collections. O3 Security detects and blocks CVE-2015-6420 exploitation at runtime via eBPF exploit-chain detection and L7 egress monitoring, even on unpatched systems.
Serialized-object interfaces in certain Cisco Collaboration and Social Media; Endpoint Clients and Client Software; Network Application, Service, and Acceleration; Network and Content…
Description
Serialized-object interfaces in certain Cisco Collaboration and Social Media; Endpoint Clients and Client Software; Network Application, Service, and Acceleration; Network and Content Security Devices; Network Management and Provisioning; Routing and Switching - Enterprise and Service Provider; Unified Computing; Voice and Unified Communications Devices; Video, Streaming, TelePresence, and Transcoding Devices; Wireless; and Cisco Hosted Services products allow remote attackers to execute arbitrary commands via a crafted serialized Java object, related to the Apache Commons Collections (ACC) library.
Affected Products
commons collectionsapacheDetection & mitigation playbook
Vendor / applianceDetect
Inventory every apache commons collections deployment and check each version against the affected-products list above. Because the exploit targets the running system rather than your application code, also watch for remote code execution at the network and runtime layer — O3 flags the exploit behaviour from runtime telemetry and egress traffic even before a vulnerable build is confirmed.
Fix
Apply the apache commons collections security patch or hotfix for CVE-2015-6420 on the affected version, following the vendor advisory for your exact build.
Workarounds
Cut exposure now: restrict the management/admin interface to trusted networks, segment the device, and apply the vendor's recommended configuration mitigations and any WAF/IPS signature. O3's runtime protection blocks the exploit chain at execution, holding the line on unpatched or end-of-life systems until you can patch.
How O3 protects you
O3 detects and blocks CVE-2015-6420 exploitation at runtime: eBPF exploit-chain detection, plus L7 egress monitoring that catches the post-exploitation callback and severs the attacker's outbound channel.
Tailored to CVE-2015-6420. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2015-6420 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2015-6420 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.