Known exploited · Sunhillo

CVE-2021-36380: Sunhillo SureLine OS Command Injection Vulnerablity

What it is

Sunhillo SureLine contains an OS command injection vulnerability that allows an attacker to cause a denial-of-service or utilize the device for persistence on the network via shell metacharacters in ipAddr or dnsAddr in /cgi/networkDiag.cgi.

Added March 5, 2024Due March 26, 2024CISA KEV catalog 2026.10.01

Vendor: Sunhillo
Product: SureLine
Added to KEV: March 5, 2024
CISA due date: March 26, 2024
Ransomware use: Unknown
Weakness: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

What CISA requires

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Forensic triage

What to do now

Find every instance of SureLine you run, including the forgotten ones, and check its version against the vendor advisory.
Apply the vendor's fix or mitigation, before March 26, 2024 if you are bound by CISA's deadline, sooner if it faces the internet.
Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
Until every instance is patched, block the attack at the edge: a WAF in blocking mode stops OS command injection payloads, including Shellshock.

References

CVE-2021-36380 in the National Vulnerability Database

The Dome

Block it at the edge while you patch

The Dome's WAF runs the OWASP Core Rule Set in blocking mode and stops OS command injection payloads, including Shellshock before they reach your application.

See the Dome

T Academy

Train the engineers who fix it

Security engineering on real hosts in the browser, every objective checked on the machine. The first two lessons of Linux 1 are free.

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Source: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.