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Questions tagged [snort]

Snort is an open source network intrusion detection and prevention system (NIDS/NIPS).

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How to determine TLS traffic in snort signature

I am trying to have a snort signature that can detect encrypted traffic but I am not able to determine the TLS traffic using a snort signature. The content keyword search in the payload of the packet,...
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77 views

Snort rule to detect non-TLS traffic [closed]

I am having trouble creating a snort rule that will allow me to detect unencrypted traffic. My goal is to detect any unencrypted traffic. I was thinking to create a rule that if it doesn't match ...
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45 views

Are these snort alerts false positives or attacks?

Can anyone describe this alert please? I am confused if an attack is run against my network or not. I run snort IDS/IPS through a pfsense firewall.
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In Snort for Windows, how do I limit log file size, keep that file, and make another file instance

I have Snort for Windows. I am trying to make a log file of say size limit 1MB. When the log file hits the 1MB maximum, I want it to close that file (snort.log.1234567890) and open a new log file ...
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30 views

Snort CSV details @ alert

I have enabled the fast logging mode, my question here is how can I extract the CVE details or reference tag inside the /var/log/alert file, as if now I am able to see only this much data in alert ...
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3answers
2k views

Threshold for DDOS Attack

I am trying to understand and simulate SYN Flood DDOS attacks. I am using snort to give me alerts. While I have control over the rate for my testing, I am interested in knowing what a good estimate of ...
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1answer
178 views

How to sniff VPN traffic using Snort?

Here's what I want to do: I want to use a VPN client on my PC (like TunnelBear). Then I want to use Snort to sniff traffic before it's encrypted and after it's decrypted by VPN. So basically I want ...
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1answer
120 views

Loopback with Suricata

Is there any way of analyzing loopback traffic with Suricata? I am trying it this way without success: root@security-onion:/home/sar/TFM/alerts/suricata# suricata -c /etc/suricata/suricata.yaml -i ...
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1answer
116 views

Analyzing Apache log with Snort

I need to analyze an Apache log with Snort and others IDS/WAFs (Suricata, mod_security and Shadow Daemon). In order to do so, I was thinking about create TCP packets with the GET and POST requests ...
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0answers
75 views

Are these Snort rules correct?

I wrote this rule so that when there are more than three failed SSH connection attempts that there is an alert but it is not working. Are these rules badly written? Or if not I ask the exact writing ...
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120 views

snort rules are enabled by pulledpork but in the same time are skipped?

I am using pulledpork for management of rules. I had enabled rules from 1:1000 to 1:5735 those rules are enabled but in the same time are skipped. As output I had: https://github.com/shirkdog/...
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Snort not working with IDSWakeup

I have setup Snort with the registered user rules installed. I tested first by making the following rule in local.rules: alert icmp any any -> $HOME_NET any (msg:"ICMP test"; sid:10000001; rev:...
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168 views

How can I get Suricata to alert on 1 packet every time

I am trying to write a Suricata signature for testing purposes to alert every time it is triggered with a single PCAP file containing a single packet, but this is proving to be harder than I thought. ...
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0answers
26 views

0 dynamic rules read

I am running Snort as IDS in Security Onion and get this message: 0 Dynamic rules All SO_RULES are loaded in snort.conf in the correct path. 25867 Snort rules read 23950 detection rules ...
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4answers
889 views

Benefit of using two network interfaces for intrusion detection system

What is the benefit of using two network interfaces (management interface and sniffing interface) for an IDS such as Snort? I have used a Snort IDS where it only used one network interface for both ...
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2answers
211 views

how to write a snort rule to alert traffic that does not find any matched rules

Snort in IDS mode: If there is some traffic that does NOT find any matched rule against all existing Snort rules, how would you write a bottom rule to alert this traffic?
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1answer
218 views

pcap files for simulated attacks on SCADA systems?

I need to get hold of some pcap files belonging to a simulated attack on SCADA systems. My goal is to then use Snort for the detection. Or if somebody can suggest a practical environment to create my ...
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0answers
312 views

Snort.log output as unreadable symbols

I have recently installed Snort IDS on Linux Ubuntu 16.04LTS (not server), after experimenting and testing configuration in VitualBox. After installing and successfully validating the configuration ...
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1answer
153 views

How do I map the information in snort u2spewfoo output to the rule which triggered the alert?

I have a snort log file in unified2 format and I am able to view the output using the u2spewfoo utility. I think that I understand the generator id, signature id, and revision tell me why the alert ...
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2answers
458 views

Snort Exercises

I am beginning to study Snort rules and the teacher give to us the next exercises: A server on which Snort is installed is monitoring all traffic on subnet 172.16.0.0 with mask 255.255.0.0. From now ...
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213 views

Snort pcap mapping with kibana

I am working on project which has four entities (snort,logstash,elasticsearch,kibana).I am maintaining snort which is deployed in Centos 7, snort puts a metadata in alert file(/var/log/alert) this ...
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0answers
72 views

snort add more data in alert file

I want to add more data to alert file rightnow the data what our analyst team see is very minimal and we are not giving access to them to our snort backend server, our design is like centos /var/log/...
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1answer
1k views

Snort priority range

What is the range of values for the 'priority' parameter in a Snort rule? The documentation it doesn't make it clear: The priority tag assigns a severity level to rules. A classtype rule assigns a ...
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1answer
266 views

Security Onion VMWare + OpenWRT IPTables Mirroring

I'm trying to set up SO in my home network to lab and see if I can monitor all ingress/egress traffic from my SOHO router. I don't have a switch with SPAN ports, or a network tap so I'm using OpenWRT ...
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1answer
548 views

How to detect a string in HTML with Snort?

I am trying to detect a string in HTML (already unzipped) with Snort. I set this rule to find content 7038685658 in my Apache web server's HTML: alert tcp any any <> any any (msg:"cell"; ...
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1answer
929 views

IDS Snort rule to catch Slow-Loris

I'm trying to write a rule to catch a Slow-Loris attack, this is what i have - alert tcp any any -> any any (msg:"Possible Slow Loris attack"; classtype: denial-of-service; flow: to_server, ...
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1answer
233 views

Suricata does not detect “self” traffic

I have built two simple rules alert tcp any any -> any any (msg: "tcp detected"; sid: 2; rev: 1;) alert udp any any -> any any (msg: "udp detected"; sid: 1; rev: 1;) Then from the same machine ...
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2answers
190 views

Can dual NIC Snort machine cause threats to bypass firewall?

I am thinking about building a Linux Snort machine that can listen to both WAN and LAN traffic. Setup I am thinking about: Snort computer with two NICs One NIC connected to hub/tap outside firewall (...
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119 views

Using snortsam on preprocessor rules

I am using snortsam to block IP addresses. I can't use inline mode and nfqueue as it considerably decreases network traffic performance. Currently I am trying to detect TCP protocol anomalies and ...
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0answers
113 views

snort file_inspect signature working inconsistently [closed]

I am trying snorts file inspect preprocessor for blocking incoming files from their sha256sums. I am using snort version 2.9.9.0 with daq nfq inline mode any my file_inspect preprocessor configs are ...
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1answer
274 views

Snort: Cannot decode data link type 127 reading a pcapng file

I've captured on my wifi some days ago and now I want snort to analyse the capture to detect any problem. However, when I run snort -l ./snort-log -b -c /etc/snort/snort.conf -r captura-analisar....
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2answers
164 views

How to detect long lived SSH sessioned

I am trying to figure out a way to detect ssh sessions that have been established over a long period of time. I seem to recall that there were ways to detect tcp connections that have been connected ...
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2answers
1k views

Major differences between Snort and Snort 3.0

When I visited the the Snort's website to download the source code for compilation, I found there were 2 downloads available. One was titled Snort and another was titled Snort 3.0 Has the ...
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2answers
343 views

REJECT Nikto Scans With Snort Rules

Hoping someone on here knows a way to reject Nikto traffic with Snort rules. I've been having zero luck for days finding this anywhere online. Thanks. Peace.
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226 views

how to use snort to track http/https sessions separately?

how can I use snort to breakdown http/https traffic into separate sessions and track each session separately and also dump them into separate log files or something that I can read from.
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3answers
8k views

Can Snort run on a Raspberry Pi?

I am in the preliminary stages of designing a cybersecurity suite for my home network. I don't have any servers or anything, just the standard home setup (computers, tablets, game consoles). The ...
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1answer
251 views

Can I run Snort on a slow computer?

I'm trying to use a device with 1GB of RAM and a Single 800 MHz core CPU. I will use Snort to analyze traffic on my LAN network. Snort, unfortunately, cannot analyze all the traffic (sometimes it ...
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0answers
86 views

Signature Generate by Honeyd “Honeycomb” is not accept by Snort IPS

I posted this on SO [https://stackoverflow.com/questions/44652014/signature-generate-by-honeyd-honeycomb-is-not-accept-by-snort-ips] is this on topic here? What would I need to do to my question ? I ...
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1answer
406 views

Snort Alert - What is PROTO:255?

My Snort alert output is like below. The first element of 4th row of each alert indicates Protocol. However, in the alert (portscan) TCP Portscan, the protocol is PROTO:255. What does it mean? Why ...
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394 views

Snort rules uricontent

I am experiencing trouble crating rules that would check user HTTP behaviour (page address, POST/GET params..). alert tcp any any -> any any (msg:"Alfa in uri"; flow:to_server,established; ...
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0answers
235 views

Detecting Guest to Guest Traffic in Virtualbox Using Host Running Snort

Not sure if this is a simple question but I was hoping for some insight into finishing a pentest lab. My goal is to have Snort sniff an attack in a virtual environment between two guest VM's. My ...
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0answers
201 views

How to log only the TCP header using command line in snort or nmap? [closed]

I work with snort log file and now I need to extract the TCP header. My question is: How to log only the TCP header from the packets captured by snort log file (without the payload) using command ...
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2answers
2k views

How does the flow option of Snort work?

For example, flow:established is detecting only for packets with sessions connected. Then, the server is rejecting packets to received after the session is disconnected?
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1answer
515 views

Troubleshooting Snort Rules

I am trying to troubleshoot a bunch of flowbits generated by pulledpork from snortrules-snapshot-2990.tar.gz. WARNING: flowbits key 'file.pdf' is set but not ever checked. The line in the generated ...
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0answers
211 views

Snort generates an alert that is empty [closed]

I am working with commands that have already been tested to work but they aren't working now. This is my config file: alert tcp any any <> any any (msg: "/etc/passwd Payload Found"; content: "/...
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1answer
263 views

How to inspect TCP Header -> Optional Data with Snort?

I have been looking around for clues on how to define rules, decoders or preprocessors to be able to content-inspect the TCP Header's Optional Data ( The last 0-40 bytes of the TCP Header) TCP ...
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1answer
413 views

Where can I find a snort signature for detecting slowhttp DoS attack from Slowloris tool [duplicate]

I am performing a test on some DoS attacks and how to detect them. I am currently testing the slowloris tool, but all the signature I have seen online, as very very few as they are,do not work even ...
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161 views

SourceFire/Snort/FirePower Custom Regex Rule Error

I am getting an unknown/extra pcre option encounterederror when trying to save my custom rule. ^([A-HK-PRSVWY][A-HJ-PR-Y])\s?([0][2-9]|[1-9][0-9])\s?[A-HJ-PR-Z]{3}$ The rule is to match UK Vehicle ...
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1answer
432 views

Use Snort to limit or prioritize application bandwidth usage [closed]

Short version of a long story, we've been using bluecoat packetshapers for bandwidth control on a multi-tenant network. We like it because it allows us to divide the bandwidth equally, but still allow ...
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0answers
99 views

Snort Rules Data Structure

the IDS programm Snort uses a linked list to organize rules (ORT/OTN). This list is used in run time. How it is possible to view this data structure in run time? Any tip would be helpful. Thanks in ...