CVE-2021-3378
CRITICALFortiLogger 4.4.2.2 is affected by Arbitrary File Upload by sending a "Content-Type: image/png" header to Config/SaveUploadedHotspotLogoFile and then visiting Assets/temp/hotspot/img/logohotspot.asp.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Description
FortiLogger 4.4.2.2 is affected by Arbitrary File Upload by sending a "Content-Type: image/png" header to Config/SaveUploadedHotspotLogoFile and then visiting Assets/temp/hotspot/img/logohotspot.asp.
Affected Products
fortiloggerfortiloggerResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
FortiLogger 4.4.2.2 - Unauthenticated Arbitrary File Upload (Metasploit)
by Berkan Er · Mar 1, 2021
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every fortilogger fortilogger 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 exploitation 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 fortilogger fortilogger security patch or hotfix for CVE-2021-3378 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-2021-3378 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-2021-3378. 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-2021-3378 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2021-3378 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.