Suricata Coverage for Log4Shell Exploitation Attempts (CVE-2021-44228)

log4shell-exploitation-attempts.rules

# Detects Log4j exploitation attempts
alert http any any -> $HOME_NET any (msg:"FOX-SRT - Exploit - Possible Apache Log4J RCE Request Observed (CVE-2021-44228)"; flow:established, to_server; content:"${jndi:ldap://"; fast_pattern:only; flowbits:set, fox.apachelog4j.rce; threshold:type limit, track by_dst, count 1, seconds 3600; classtype:web-application-attack; priority:3; reference:url, www.lunasec.io/docs/blog/log4j-zero-day/; metadata:CVE 2021-44228; metadata:created_at 2021-12-10; metadata:ids suricata; sid:21003726; rev:1;) 

alert http any any -> $HOME_NET any (msg:"FOX-SRT - Exploit - Possible Apache Log4J RCE Request Observed (CVE-2021-44228)"; flow:established, to_server; content:"${jndi:"; fast_pattern; pcre:"/\$\{jndi\:(rmi|ldaps|dns)\:/"; flowbits:set, fox.apachelog4j.rce; threshold:type limit, track by_dst, count 1, seconds 3600; classtype:web-application-attack; priority:3; reference:url, www.lunasec.io/docs/blog/log4j-zero-day/; metadata:CVE 2021-44228; metadata:created_at 2021-12-10; metadata:ids suricata; sid:21003728; rev:1;) 

alert http any any -> $HOME_NET any (msg:"FOX-SRT - Exploit - Possible Defense-Evasive Apache Log4J RCE Request Observed (CVE-2021-44228)"; flow:established, to_server; content:"${jndi:"; fast_pattern; content:!"ldap://"; flowbits:set, fox.apachelog4j.rce; threshold:type limit, track by_dst, count 1, seconds 3600; classtype:web-application-attack; priority:3; reference:url, www.lunasec.io/docs/blog/log4j-zero-day/; reference:url, twitter.com/stereotype32/status/1469313856229228544; metadata:CVE 2021-44228; metadata:created_at 2021-12-10; metadata:ids suricata; sid:21003730; rev:1;) 

alert http any any -> $HOME_NET any (msg:"FOX-SRT - Exploit - Possible Defense-Evasive Apache Log4J RCE Request Observed (URL encoded bracket) (CVE-2021-44228)"; flow:established, to_server; content:"%7bjndi:"; nocase; fast_pattern; flowbits:set, fox.apachelog4j.rce; threshold:type limit, track by_dst, count 1, seconds 3600; classtype:web-application-attack; priority:3; reference:url, www.lunasec.io/docs/blog/log4j-zero-day/; reference:url, https://twitter.com/testanull/status/1469549425521348609; metadata:CVE 2021-44228; metadata:created_at 2021-12-11; metadata:ids suricata; sid:21003731; rev:1;) 

alert http any any -> $HOME_NET any (msg:"FOX-SRT - Exploit - Possible Apache Log4j Exploit Attempt in HTTP Header"; flow:established, to_server; content:"${"; http_header; fast_pattern; content:"}"; http_header; distance:0; flowbits:set, fox.apachelog4j.rce.loose; classtype:web-application-attack; priority:3; threshold:type limit, track by_dst, count 1, seconds 3600; reference:url, www.lunasec.io/docs/blog/log4j-zero-day/; reference:url, https://twitter.com/testanull/status/1469549425521348609; metadata:CVE 2021-44228; metadata:created_at 2021-12-11; metadata:ids suricata; sid:21003732; rev:1;) 

alert http any any -> $HOME_NET any (msg:"FOX-SRT - Exploit - Possible Apache Log4j Exploit Attempt in URI"; flow:established,to_server; content:"${"; http_uri; fast_pattern; content:"}"; http_uri; distance:0; flowbits:set, fox.apachelog4j.rce.loose; classtype:web-application-attack; priority:3; threshold:type limit, track by_dst, count 1, seconds 3600; reference:url, www.lunasec.io/docs/blog/log4j-zero-day/; reference:url, https://twitter.com/testanull/status/1469549425521348609; metadata:CVE 2021-44228; metadata:created_at 2021-12-11; metadata:ids suricata; sid:21003733; rev:1;) 


# Better and stricter rules, also detects evasion techniques
alert http any any -> $HOME_NET any (msg:"FOX-SRT - Exploit - Possible Apache Log4j Exploit Attempt in HTTP Header (strict)"; flow:established,to_server; content:"${"; http_header; fast_pattern; content:"}"; http_header; distance:0; pcre:/(\$\{\w+:.*\}|jndi)/Hi; xbits:set, fox.log4shell.attempt, track ip_dst, expire 1; threshold:type limit, track by_dst, count 1, seconds 3600; classtype:web-application-attack; reference:url,www.lunasec.io/docs/blog/log4j-zero-day/; reference:url,https://twitter.com/testanull/status/1469549425521348609; metadata:CVE 2021-44228; metadata:created_at 2021-12-11; metadata:ids suricata; priority:3; sid:21003734; rev:1;) 

alert http any any -> $HOME_NET any (msg:"FOX-SRT - Exploit - Possible Apache Log4j Exploit Attempt in URI (strict)"; flow:established, to_server; content:"${"; http_uri; fast_pattern; content:"}"; http_uri; distance:0; pcre:/(\$\{\w+:.*\}|jndi)/Ui; xbits:set, fox.log4shell.attempt, track ip_dst, expire 1; classtype:web-application-attack; threshold:type limit, track by_dst, count 1, seconds 3600; reference:url,www.lunasec.io/docs/blog/log4j-zero-day/; reference:url,https://twitter.com/testanull/status/1469549425521348609; metadata:CVE 2021-44228; metadata:created_at 2021-12-11; metadata:ids suricata; priority:3; sid:21003735; rev:1;) 

alert http any any -> $HOME_NET any (msg:"FOX-SRT - Exploit - Possible Apache Log4j Exploit Attempt in Client Body (strict)"; flow:to_server; content:"${"; http_client_body; fast_pattern; content:"}"; http_client_body; distance:0; pcre:/(\$\{\w+:.*\}|jndi)/Pi; flowbits:set, fox.apachelog4j.rce.strict; xbits:set,fox.log4shell.attempt,track ip_dst,expire 1; classtype:web-application-attack; threshold:type limit, track by_dst, count 1, seconds 3600; reference:url,www.lunasec.io/docs/blog/log4j-zero-day/; reference:url,https://twitter.com/testanull/status/1469549425521348609; metadata:CVE 2021-44228; metadata:created_at 2021-12-12; metadata:ids suricata; priority:3; sid:21003744; rev:1;)