CVE-2023-28343

What it actually does

The flaw is an unauthenticated network-reachable OS command injection in Altenergy/APsystems energy control software. The timezone parameter submitted to index.php/management/set_timezone is incorporated into server-side shell execution without sufficient sanitization, allowing shell metacharacters to break out of the intended timezone-setting operation and execute arbitrary operating-system commands with the privileges of the web application or underlying device process. Because the CVSS vector is AV:N/AC:L/PR:N/UI:N and impact is high for confidentiality, integrity, and availability, successful exploitation can provide full device compromise, data access, configuration tampering, service disruption, and a foothold for lateral movement depending on network placement.

Why it matters to the business

Compromise of affected energy communication/control units can disrupt solar or energy-management operations, alter device configuration, expose operational data, and give attackers a foothold inside networks that trust these devices. The high CVSS score, high EPSS probability, and weaponized exploit maturity make this a high-priority exposure even though it is not currently listed in CISA KEV. Since no fixed version is provided in the supplied data, organizations may need to rely on vendor advisories, replacement firmware when available, network isolation, and access control until a confirmed patch is available.

How an attack unfolds

An attacker first identifies an exposed APsystems/Altenergy energy communication unit or management interface reachable over the network. They send a crafted HTTP request to index.php/management/set_timezone with shell metacharacters embedded in the timezone parameter. The vulnerable backend code in models/management_model.php passes that value into an OS command without safely escaping or validating it, causing the attacker-supplied command to execute on the device. From there, the attacker can run reconnaissance commands, modify configuration, create persistence if the platform permits it, retrieve sensitive operational data, disable services, pivot to other reachable systems, or use the device in broader botnet or disruption activity.

How to fix it

Upgrade affected APsystems/Altenergy energy communication unit firmware or Altenergy Power Control Software to a vendor-confirmed fixed release as soon as one is available. No exact fixed version was provided in the input, so consult the vendor’s security advisory or support channel for the applicable model and firmware branch. Until a fix is confirmed, remove the management interface from internet exposure, restrict access to trusted administrative networks or VPNs, enforce firewall allowlists, disable unnecessary remote management, and place energy control devices on segmented networks with no direct path to enterprise assets. If the device supports configuration hardening, require strong authentication for all management functions, disable default credentials, and monitor or block suspicious requests containing command separators in the timezone parameter. Where patching is unavailable or unsupported, plan replacement or isolation of affected devices.

How to confirm the fix worked

Confirm the running firmware/software version and compare it with the vendor’s security advisory for CVE-2023-28343 or any corrected APsystems/Altenergy firmware release. Verify that index.php/management/set_timezone is not accessible from the internet and is reachable only from authorized administrative networks. Use a safe, non-destructive test in an authorized environment to submit benign shell metacharacters in the timezone parameter and confirm they are rejected, sanitized, or logged without execution. Review web server, application, reverse proxy, firewall, and IDS logs for requests to the vulnerable endpoint, especially requests containing characters such as ;, |, &, `, $(), >, <, or URL-encoded equivalents. After remediation, rescan externally and internally to confirm the management endpoint is not exposed beyond intended access paths.

Typical attack path

1. Scan the internet or internal network for exposed APsystems/Altenergy energy communication unit web interfaces.
2. Confirm the target exposes the vulnerable management endpoint, such as index.php/management/set_timezone.
3. Send a crafted request with shell metacharacters in the timezone parameter to test command execution.
4. Execute operating-system discovery commands to determine user context, filesystem layout, network access, and installed tooling.
5. Deploy follow-on commands or payloads to change configuration, collect data, establish persistence, or disrupt device operation.
6. Use the compromised device as a foothold to reach other systems or as infrastructure for further malicious activity.

How to detect it

Look for evidence of HTTP requests to index.php/management/set_timezone with suspicious timezone parameter values containing shell metacharacters, command substitution, URL-encoded command separators, or common reconnaissance commands. Relevant log sources include embedded device web logs, reverse proxy logs, WAF logs, firewall logs, IDS/IPS alerts, VPN access logs, and any centralized syslog from the energy communication units. Search for requests using POST or GET to the set_timezone endpoint that include characters such as semicolon, pipe, ampersand, backticks, $(), redirection operators, or encoded forms like %3B, %7C, %26, %60, %24%28, %3E, and %3C. Also look for outbound connections from the device to unusual IP addresses shortly after such requests, unexpected DNS lookups, process execution anomalies if telemetry is available, configuration changes, new files in writable web or temporary directories, unexplained service restarts, and device time zone changes occurring outside normal administration. Since this vulnerability is weaponized, investigate both failed probes and apparently successful requests, especially those followed by commands such as id, whoami, uname, wget, curl, busybox, nc, sh, or chmod.

• /index.php/management/set_timezone
• timezone=
• set_timezone
• management_model.php
• timezone=%3B
• timezone=;
• timezone=%7C
• timezone=|
• timezone=%26
• timezone=&
• timezone=%60
• timezone=`
• timezone=$(
• timezone=%24%28
• timezone=%3E
• timezone=>
• timezone=%3C
• timezone=<
• /index.php/management/set_timezone?timezone=
• POST /index.php/management/set_timezone
• GET /index.php/management/set_timezone
• whoami
• uname -a
• /bin/sh
• /bin/busybox
• busybox wget
• wget http
• curl http
• chmod +x
• /tmp/
• nc -e
• /dev/tcp/

What your security team should do

• Treat this as high priority because exploitation is weaponized, the EPSS score is high, and exploitation requires no authentication or user interaction.
• Immediately inventory APsystems/Altenergy energy communication units and identify any internet-facing or broadly reachable management interfaces.
• Remove public exposure and restrict management access with firewall allowlists, VPN, or dedicated administrative networks.
• Check vendor guidance for fixed firmware/software and upgrade or replace affected devices where a fixed release is available.
• Deploy WAF, reverse proxy, IDS, or firewall rules to alert on and block requests to /index.php/management/set_timezone containing shell metacharacters or encoded command separators.
• Review historical logs for exploitation attempts and successful command execution indicators before assuming patching alone is sufficient.
• Segment energy control devices from corporate, identity, database, and server networks to limit pivot opportunities.
• If compromise is suspected, preserve logs, capture device configuration and firmware state, rotate any credentials stored on or used by the device, and consider factory reset/reimage or replacement.