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I am using suricata with emerging-scan.rules and other rules. The rules are loaded in the suricata.yaml, homenet and ext_net are configured correctly. For testing detection of suricata I used nmap -sS in the machine in which suricata is installed. But nothing got detected.

As rules to detect the nmap -sS I used the following emergin-scan.rules:

alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN NMAP -sS window 2048"; fragbits:!D; dsize:0; flags:S,12; ack:0; window:2048; threshold: type both, track by_dst, count 1, seconds 60; reference:url,doc.emergingthreats.net/2000537; classtype:attempted-recon; sid:2000537; rev:8; metadata:created_at 2010_07_30, updated_at 2010_07_30;)
alert  ip $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN NMAP -sO"; dsize:0; ip_proto:21; threshold: type both, track by_dst, count 1, seconds 60; reference:url,doc.emergingthreats.net/2000536; classtype:attempted-recon; sid:2000536; rev:7; metadata:created_at 2010_07_30, updated_at 2010_07_30;)
alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN NMAP -sS window 1024"; fragbits:!D; dsize:0; flags:S,12; ack:0; window:1024; threshold: type both, track by_dst, count 1, seconds 60; reference:url,doc.emergingthreats.net/2009582; classtype:attempted-recon; sid:2009582; rev:3; metadata:created_at 2010_07_30, updated_at 2010_07_30;)
alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN NMAP -sS window 3072"; fragbits:!D; dsize:0; flags:S,12; ack:0; window:3072; threshold: type both, track by_dst, count 1, seconds 60; reference:url,doc.emergingthreats.net/2009583; classtype:attempted-recon; sid:2009583; rev:3; metadata:created_at 2010_07_30, updated_at 2010_07_30;)
alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN NMAP -sS window 4096"; fragbits:!D; dsize:0; flags:S,12; ack:0; window:4096; threshold: type both, track by_dst, count 1, seconds 60; reference:url,doc.emergingthreats.net/2009584; classtype:attempted-recon; sid:2009584; rev:2; metadata:created_at 2010_07_30, updated_at 2010_07_30;)
Steffen Ullrich
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frank
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1 Answers1

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I'm not sure if it was the case when you posted this question, but all of the signatures you posted above have been commented out of the emerging-scan.rules.

https://rules.emergingthreats.net/open/suricata-5.0/rules/emerging-scan.rules

Here are all of the remaining nmap rules in that library that are not commented out.

alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN Nmap Scripting Engine User-Agent Detected (Nmap NSE)"; flow:to_server,established; content:"Nmap NSE"; http_user_agent; reference:url,doc.emergingthreats.net/2009359; classtype:web-application-attack; sid:2009359; rev:4; metadata:created_at 2010_07_30, updated_at 2010_07_30;)

alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN Nmap Scripting Engine User-Agent Detected (Nmap Scripting Engine)"; flow:to_server,established; content:"Mozilla/5.0 (compatible|3b| Nmap Scripting Engine"; nocase; http_user_agent; depth:46; reference:url,doc.emergingthreats.net/2009358; classtype:web-application-attack; sid:2009358; rev:5; metadata:created_at 2010_07_30, updated_at 2010_07_30;)

alert http $EXTERNAL_NET any -> $HTTP_SERVERS any (msg:"ET SCAN NMAP SQL Spider Scan"; flow:established,to_server; content:"GET"; http_method; content:" OR sqlspider"; http_uri; reference:url,nmap.org/nsedoc/scripts/sql-injection.html; classtype:web-application-attack; sid:2013778; rev:2; metadata:created_at 2011_10_19, updated_at 2011_10_19;)

alert tcp $EXTERNAL_NET any -> $HOME_NET $HTTP_PORTS (msg:"ET SCAN NMAP SIP Version Detect OPTIONS Scan"; flow:established,to_server; content:"OPTIONS sip|3A|nm SIP/"; depth:19; classtype:attempted-recon; sid:2018317; rev:1; metadata:created_at 2014_03_25, updated_at 2014_03_25;)

alert tcp $EXTERNAL_NET any -> $HOME_NET 5060:5061 (msg:"ET SCAN NMAP SIP Version Detection Script Activity"; content:"Via|3A| SIP/2.0/TCP nm"; content:"From|3A| <sip|3A|nm@nm"; within:150; fast_pattern; classtype:attempted-recon; sid:2018318; rev:1; metadata:created_at 2014_03_25, updated_at 2014_03_25;)

alert udp $EXTERNAL_NET 10000: -> $HOME_NET 10000: (msg:"ET SCAN NMAP OS Detection Probe"; dsize:300; content:"CCCCCCCCCCCCCCCCCCCC"; fast_pattern:only; content:"CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC"; depth:255; content:"CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC"; within:45; classtype:attempted-recon; sid:2018489; rev:3; metadata:created_at 2014_05_20, updated_at 2014_05_20;)

alert tcp any any -> $HOME_NET any (msg:"ET SCAN Nmap NSE Heartbleed Request"; flow:established,to_server; content:"|18 03|"; depth:2; byte_test:1,<,4,2; content:"|01|"; offset:5; depth:1; byte_test:2,>,2,3; byte_test:2,>,200,6; content:"|40 00|Nmap ssl-heartbleed"; fast_pattern:2,19; classtype:attempted-recon; sid:2021023; rev:1; metadata:created_at 2015_04_28, updated_at 2015_04_28;)

alert tcp $HOME_NET any -> any any (msg:"ET SCAN Nmap NSE Heartbleed Response"; flow:established,from_server; content:"|18 03|"; depth:2; byte_test:1,<,4,2; byte_test:2,>,200,3; content:"|40 00|Nmap ssl-heartbleed"; fast_pattern:2,19; classtype:attempted-recon; sid:2021024; rev:1; metadata:created_at 2015_04_28, updated_at 2015_04_28;)

alert http $HOME_NET any -> any any (msg:"ET SCAN Possible Nmap User-Agent Observed"; flow:to_server,established; content:"|20|Nmap"; http_user_agent; fast_pattern; metadata: former_category SCAN; classtype:web-application-attack; sid:2024364; rev:3; metadata:affected_product Any, attack_target Client_and_Server, deployment Perimeter, signature_severity Audit, created_at 2017_06_08, performance_impact Low, updated_at 2017_06_13;)

I did try to trigger them, but I don't really have the right setup to try as most of them require external to internal connections.

MikeSchem
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