CVE-2018-16763

published 2018-09-09

CVE-2018-16763: FUEL CMS 1.4.1 allows PHP Code Evaluation via the pages/select/ filter parameter or the preview/ data parameter. This can lead to Pre-Auth Remote Code…

Priority P1 91 critical 9.8 CVSS 3.1

AV N AC L PR N UI N S U C H I H A H

ITW EXPLOIT VulnCheck KEV Initial access

FUEL CMS 1.4.1 allows PHP Code Evaluation via the pages/select/ filter parameter or the preview/ data parameter. This can lead to Pre-Auth Remote Code Execution.

Affected

1 ranges

Vendor	Product	Version range	Fixed in
thedaylightstudio	fuel_cms	<= 1.4.2	—

Detection & IOCs extracted from sources · hover to see the quote

url /fuel/pages/select/?filter=%27%2bpi(print(%24a%3d%27system%27))%2b%24a(%27cat%20/etc/passwd%27)%2b%27↗

url /fuel/pages/select/?filter=%27%2b%70%69%28%70%72%69%6e%74%28%24%61%3d%27%73%79%73%74%65%6d%27%29%29%2b%24%61%28%27↗

url /fuel/pages/select/?filter='%2Bpi(print(%24a%3D'system'))%2B%24a('<cmd>')%2B'↗

path /fuel/pages/select/↗

snort

alert http any any -> [$HTTP_SERVERS,$HOME_NET] any (msg:"ET EXPLOIT Fuel CMS 1.4.1 RCE (CVE-2018-16763)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/fuel/pages/select/"; fast_pattern; content:"filter=|27 2b|"; content:"|2b 27|"; distance:0; reference:url,github.com/daylightstudio/FUEL-CMS/issues/478; reference:url,cybersecurity.att.com/blogs/labs-research/rapidly-evolving-iot-malware-enemybot-now-targeting-content-management-system-servers; reference:cve,2018-16763; classtype:attempted-admin; sid:2036748; rev:2; metadata:attack_target Server, created_at 2022_06_02, cve CVE_2018_16763, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag Exploit, updated_at 2024_06_23, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;)

bytes

filter=|27 2b| ... |2b 27|

• → Exploit targets GET requests to /fuel/pages/select/ with a `filter` parameter containing URL-encoded PHP code injection using pi(print(...)) pattern. Look for `filter=` followed by percent-encoded single-quotes and `pi(` or `system` strings. ↗
• → The attack is Pre-Auth (no authentication required). Any GET to /fuel/pages/select/?filter= with encoded PHP eval payload should be treated as an exploitation attempt regardless of session state. ↗
• → Shodan/FOFA fingerprinting queries used by attackers to discover targets: search for HTTP title 'fuel cms' or page title 'fuel cms'.
• → The exploit also abuses the preview/ data parameter as an alternative injection point. Monitor POST/GET requests to /fuel/preview/ with a `data` parameter containing PHP code.
• → Exploit traffic uses a local proxy on 127.0.0.1:8080 in some variants; however the key network indicator is the URI pattern, not the proxy. ↗

• · The Nuclei template uses a benign test command (cat /etc/passwd) and matches on 'root:.*:0:0:' in the response to confirm RCE. Production detection rules should not rely solely on response content matching, as attackers will use different commands.
• · The Snort rule (ET sid:2036748 rev:2) matches on the URL-encoded single-quote byte sequence |27 2b| in the filter parameter. Attackers may vary encoding (e.g., double-encoding or alternate representations) to evade this specific byte pattern.

CVSS provenance

nvd v3.1 9.8 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd v2.0 7.5 HIGH AV:N/AC:L/Au:N/C:P/I:P/A:P

vulncheck 9.8 CRITICAL

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