CVE-2022-45699

What it actually does

CVE-2022-45699 is a pre-authentication command injection vulnerability in the APSystems ECU-R administration interface. The vulnerable firmware accepts user-controlled input in the timezone parameter and incorporates it into an operating-system command without adequate validation or escaping. Because the administration interface runs commands with root privileges, a remote attacker can execute arbitrary shell commands as root over the network. Successful exploitation can result in full device compromise, including reading or modifying configuration, installing persistence, changing inverter/energy-management behavior, pivoting within reachable networks, or rendering the device unavailable.

Why it matters to the business

Compromise of an APSystems ECU-R device can disrupt solar monitoring and energy-management operations, cause loss of visibility into generation data, alter device configuration, and create a foothold into adjacent networks. The CVSS score of 9.8, high EPSS probability, and weaponized exploit maturity indicate elevated real-world exploitation risk even though the issue is not currently listed in CISA KEV. Organizations with internet-exposed ECU-R administration interfaces should treat this as urgent because exploitation requires no authentication and can lead to complete device takeover.

How an attack unfolds

An attacker first identifies an APSystems ECU-R device with its administration interface reachable over the network, commonly through internet scanning or internal reconnaissance. The attacker then sends a crafted HTTP request to the vulnerable administrative endpoint containing shell metacharacters or command syntax in the timezone parameter. The firmware processes that parameter unsafely and passes it to a system command. The injected command executes as root, allowing the attacker to run arbitrary commands on the device. From there, the attacker may retrieve configuration data, change settings, download additional tooling, establish persistence, disable services, use the device for botnet activity, or attempt lateral movement into networks that the ECU-R can reach.

How to fix it

Restrict access to the APSystems ECU-R administration interface immediately, especially from the public internet. Place the device behind a firewall or VPN, allow only trusted management hosts, and block unsolicited inbound access. Upgrade ECU-R firmware to a vendor-provided fixed release if available; because no fixed version is provided in the supplied data, administrators should consult APSystems advisories or support channels for the latest firmware addressing this issue. If no fixed firmware is available, mitigate by isolating the device on a dedicated network segment, disabling remote administration where possible, enforcing management access controls at the network layer, and monitoring for suspicious administrative requests. Consider replacing devices that cannot be patched or adequately isolated.

How to confirm the fix worked

Confirm the device firmware version through the ECU-R administration interface, vendor management tooling, or local device inventory and verify it is not version 5203 or any other vendor-confirmed vulnerable release. Validate that the administration interface is not reachable from the internet using external scanning from an untrusted network. Confirm firewall rules restrict access to known management IPs only. If a firmware update is applied, re-check the reported firmware version and verify that crafted timezone values containing shell metacharacters are rejected, sanitized, or do not result in command execution. Avoid destructive testing on production devices; use controlled validation methods or vendor-provided checks where available.

Typical attack path

1. Scan for APSystems ECU-R devices with exposed web administration interfaces.
2. Confirm the target is running vulnerable firmware, including ECU-R version 5203 or another affected build.
3. Send a crafted request to the administration interface with command syntax embedded in the timezone parameter.
4. Achieve unauthenticated root-level command execution on the device.
5. Run reconnaissance commands such as id, uname, ifconfig, ps, or cat against configuration files.
6. Optionally download and execute additional payloads, create persistence, modify device configuration, or pivot to adjacent network assets.

How to detect it

To determine whether exploitation has already occurred, review HTTP access logs or reverse-proxy logs for requests to the ECU-R administration interface containing a timezone parameter with shell metacharacters, command separators, URL-encoded command syntax, or attempts to fetch remote payloads. Inspect firewall and network logs for inbound scanning followed by unusual outbound connections from the ECU-R device, especially HTTP, HTTPS, FTP, TFTP, Telnet, SSH, or connections to unfamiliar IP addresses. On the device, if shell or forensic access is available, review process lists, cron entries, init scripts, temporary directories, modified web files, and recently changed configuration files for unauthorized commands or persistence. Look for evidence of common post-exploitation commands such as id, uname, wget, curl, chmod, sh, busybox, nc, telnetd, or attempts to write files in /tmp. Because embedded devices may have limited logging, absence of logs does not prove absence of compromise; prioritize network telemetry and configuration drift analysis for exposed devices.

• timezone=;
• timezone=%3B
• timezone=|
• timezone=%7C
• timezone=`
• timezone=%60
• timezone=$(
• timezone=%24%28
• timezone=&&
• timezone=%26%26
• timezone=||
• timezone=%7C%7C
• timezone=*wget*
• timezone=*curl*
• timezone=*busybox*
• timezone=*chmod*
• timezone=*sh*
• /tmp/
• wget http://
• curl http://
• busybox wget
• chmod +x
• /bin/sh
• /bin/busybox
• telnetd
• nc -e
• rm -rf /tmp/

What your security team should do

• Immediately identify all APSystems ECU-R devices and determine whether any run firmware version 5203 or other affected firmware.
• Remove internet exposure for ECU-R administration interfaces and require VPN or tightly scoped management access.
• Upgrade to the latest APSystems ECU-R firmware that remediates the command injection vulnerability when available.
• If patching is not possible, isolate ECU-R devices on a dedicated VLAN or network segment with no unnecessary access to internal systems.
• Review web access logs, firewall logs, DNS logs, and network telemetry for suspicious requests containing command-injection characters in the timezone parameter.
• Perform compromise assessment on exposed or vulnerable devices, including review of running processes, startup scripts, unexpected files, outbound connections, and configuration changes.
• Reset device credentials and restore known-good configuration after patching or replacing any device suspected of compromise.
• Add SIEM detections for exploit attempts against the timezone parameter and for unexpected outbound traffic from ECU-R devices.