CVE-2020-10221: rConfig OS Command Injection Vulnerability

CVE-2020-10221 is an OS command injection flaw in rConfig, a network configuration management product. The issue sits in lib/ajaxHandlers/ajaxAddTemplate.php and lets a remote attacker supply shell metacharacters in the fileName POST parameter to run operating-system commands on the host. Because rConfig often holds credentials and device configs, successful abuse can give an attacker a foothold inside the management plane and a path to broader network access. Confirm all version and patch details against the vendor advisory.

How it works

The weakness is CWE-78: improper neutralization of special elements used in an OS command. When the application takes the fileName value from a POST request and passes it to a shell without adequate sanitization or parameterization, an attacker can append metacharacters that cause the shell to interpret extra commands. The CISA summary states that remote attackers can execute OS commands this way. No authentication requirement is stated in the provided facts, so treat the endpoint as potentially reachable by unauthenticated parties until you verify the opposite in your deployment and the vendor advisory. The result is arbitrary command execution in the context of the rConfig process, which typically runs with privileges sufficient to read configuration data and reach managed devices.

Am I affected? How to find it in your systems

rConfig is commonly deployed as a web application on Linux hosts used by network operations teams for backup and change management of routers, switches, and firewalls. Inventory steps:

• Search asset and CMDB records for hosts or containers labeled rConfig, and for the distinctive path lib/ajaxHandlers/ajaxAddTemplate.php.
• Scan internal web inventories and reverse-proxy configs for the rConfig application root; check package or install directories for the product name.
• Review web-server and application logs for POST requests to ajaxAddTemplate.php that contain unusual characters in the fileName parameter (semicolons, pipes, backticks, or command substitution syntax).
• Confirm the exact installed release against the vendor advisory; the facts supplied here do not list version ranges, so do not assume any build is safe without that check.

Telemetry that may indicate probing or exploitation includes unexpected child processes spawned by the web or PHP user, outbound connections from the rConfig host that do not match normal backup schedules, and sudden creation or modification of files under the application tree.

How to remediate

Patch first. CISA’s required action is to apply updates per vendor instructions. Obtain the fixed package or patch directly from the vendor, verify its integrity, and install it on every rConfig instance. After patching:

• Restart the web service and confirm the vulnerable script no longer accepts unsanitized input (re-test only in a controlled manner and only after the vendor fix is applied).
• Rotate any credentials or secrets that rConfig stored or used, because command execution could have exposed them.
• Enforce least privilege on the service account that runs rConfig so future injection flaws have a smaller blast radius.
• Ensure the application is not exposed to untrusted networks; place it behind authentication gateways and management-network controls.

If you can't patch immediately

Reduce exposure until the vendor update can be installed:

• Segment the rConfig host so only authorized management jump hosts can reach its web port; block direct internet or user-LAN access.
• If a web application firewall is available, add a temporary rule that rejects POST bodies to ajaxAddTemplate.php containing shell metacharacters; treat this as virtual patching only, not a substitute for the real fix.
• Disable or restrict the template-add functionality if operationally feasible, or remove execute permissions on the vulnerable script as a short-term brake (test impact first).
• Increase monitoring: alert on process creation by the web user, on POSTs to the ajax handler, and on anomalous file-system changes under the rConfig directory.
• Keep the host fully patched for the underlying OS and PHP stack to limit secondary abuse paths.

If your data may have been exposed

Actively exploited command-injection flaws frequently lead to credential theft, configuration exfiltration, and follow-on movement. The facts do not document ransomware use for this CVE, but any confirmed compromise should still trigger incident response: isolate the host, preserve logs, and assume secrets handled by rConfig are burned. As a quick additional check, you can run a free exposure scan of your email addresses against known breach data sets to see whether related accounts have appeared in prior leaks.