CVE-2023-43633
HIGHOn boot, the Pillar eve container checks for the existence and content of “/config/GlobalConfig/global.json”. If the file exists, it overrides the existing configuration on the device…
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
On boot, the Pillar eve container checks for the existence and content of “/config/GlobalConfig/global.json”.
If the file exists, it overrides the existing configuration on the device on boot.
This allows an attacker to change the system’s configuration, which also includes some debug functions.
This could be used to unlock the ssh with custom “authorized_keys” via the “debug.enable.ssh” key, similar to the “authorized_keys” finding that was noted before.
Other usages include unlocking the usb to enable the keyboard via the “debug.enable.usb” key, allowing VNC access via the “app.allow.vnc” key, and more.
An attacker could easily enable these debug functionalities without triggering the “measured boot” mechanism implemented by EVE OS, and without marking the device as “UUD” (“Unknown Update Detected”). This is because the “/config” partition is not protected by “measured boot”, it is mutable and it is not encrypted in any way.
An attacker can gain full control over the device without changing the PCR values, thereby not triggering the “measured boot” mechanism, and having full access to the vault.
Note:
This issue was partially fixed in these commits (after disclosure to Zededa), where the config partition measurement was added to PCR13:
• aa3501d6c57206ced222c33aea15a9169d629141
• 5fef4d92e75838cc78010edaed5247dfbdae1889.
This issue was made viable in version 9.0.0 when the calculation was moved to PCR14 but it was not included in the measured boot.
Affected Products
evelfedgeDetection & mitigation playbook
Vendor / applianceDetect
Inventory every lfedge eve 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 lfedge eve security patch or hotfix for CVE-2023-43633 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-2023-43633 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-2023-43633. 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-2023-43633 being exploited in your environment?
O3's eBPF runtime sensors and L7 egress monitoring detect and block the CVE-2023-43633 exploit chain at execution — protecting unpatched and end-of-life systems until the vendor patch is applied.