Questions tagged [snort]

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

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798 views

Security Onion: Snorby alerts show all local network source IP (public and private)

I have recently installed the Security Onion distro for Ubuntu. This distro does a great job of combining multiple tools like snort/suricata, sguil, snorby, elsa, bro ids, squert, etc. Within my ...
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127 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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77 views

Snort: Log request based on reply

I want to write a Snort rule that logs all HTTP requests where the reply contains a specific regex. Every rule I found only logs the packet it is currently evaluating (which would be the reply in my ...
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280 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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2answers
251 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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682 views

Snort Portscan Preprocessor Analysis

Remarks I really apologize if this content isn't matching the community, but I am not getting approved on snort-mailing lists and I don't know what can I do for the same, therefore I feel this can be ...
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83 views

Stateful detection in Snort

From whatever I have read of Snort, it can analyse a single packet at a time and raise an alert based on its rules. What if I wish to have a rule based on multiple packets such as analysis of a ...
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1answer
439 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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158 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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128 views

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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114 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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321 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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210 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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111 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 ...
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436 views

Snort Show OS Fingerprint Scan Detection

when I run the OS fingerprinting scan with nmap, I don't know how to detect this with snort rules. Can you suggest a method for the rules to detect this?
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148 views

Snort&Suricata content replacement rule

I have to deal with Surikata IDS and its snort-compatible ruleset. Partially I need it in IPS mode for doing output traffic modifications. For now my "modifications" looks like this: ... pass tcp 192....
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48 views

Snort Modules Tweaking

I want to tweak and add new functionalities to snort code(Preprocessor)(v2.9.8). So,i have installed snort using source code,on ubuntu 14.04,however due to unknown problems,functionalities aren't ...
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1answer
413 views

Snort false positive, yet suspicious

I have Snort installed and tuned nicely with ET Rules on my pfSense, both my pfSense and the modem are using Googles public DNS 8.8.8.8. Recently I was denied access to google.com, and by reviewing ...
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36 views

Adding Windows 7 VM as a log source/forcing the IDS inline

I'm investigating ways to add my Windows 7 VM as a log source or even run that traffic through my IDS VM and then out to the internet but I'm not entirely sure how to approach it. Does anybody have ...
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2k views

Snort gives “could not create the registry key” error for multiple kinds of operations

I've set up a host-only network in Virtualbox consisting of a Kali linux machine and a Windows 7 machine (the host is running OS X). I have Snort installed on Windows 7 and am attempting to verify ...
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192 views

Barnyard2 Can't pull xref from unified2 format

I have snort configured to log unified2 in my snort.conf file and am using barnyard2 to parse the unified2 results. It works, except I can seem to figure out to pull the event reference (xref) out of ...
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466 views

Snort sfportscan does not log in unified2 file format

I'm running Snort version 2.9.6.0 and I'm not able to log events from the sfportscan preprocessor using the unified2 file format. This is the conf (actually is the default one): preprocessor ...
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1k views

Snort not showing dropped/blocked packets

This question is about SNORT- I m basically trying to detect PING FLOOD attack. I have included the rule**(drop icmp any any -> any any (itype:8; threshold, track by_src, count 20, ...
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33 views

Detect repeating bits with snort

I am new to snort and I am trying to make a rule that will detect repeating bits in a packet. I set it to offset to the 100th bit and the depth is 105 bits. The problem I am having is I can't figure ...
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52 views

Snort Rule to check for TCP options

Lets say malformed packets are sent by attacker with improper TCP options length i.e, 50bytes,222bytes etc. Is there any way to monitor these packets having invalid tcp options set using Snort or ...
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56 views

What can be wrong with this simple Snort Rule?

i'm using snort since some weeks now and today i want to use it in order to trigger alert for some content in the case of HTTP requests. So i try a simple rule like this one in order to begin.. alert ...
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1answer
861 views

Snort rule for syn flood attacks - Limiting number of alerts

So I have a snort rule that detects syn flood attacks that looks like this: alert tcp any any -> $HOME_NET 80 (msg:”SYN Flood - SSH"; flags:S; flow: stateless; detection_filter: track by_dst, ...
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39 views

Can an IDS be used for detecting frames (not packets) from an non-authenticated station

Can an IDS, like snort, be used to detect Layer 2 network frames from a system i.e a system is trying to send a frame to the AP and whether Snort can work on the frame based on the rules?
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266 views

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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1answer
209 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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63 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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507 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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321 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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1answer
865 views

Question on SNORT Rule

I am new to SNORT and can not figure out what the following rule means: alert tcp $EXTERNAL_NET any-> $HOME_NET any (msg:"SCAN FIN"; flags: F; reference:arachnids,27;
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1k views

problem with my snort rule

I have written this rule but when I try to reload Snort it is failing. I have commented out the rule and reloaded snort; it is working so I know it's the rule. alert tcp any any -> any 5466 (msg:"...
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67 views

Possible to run snort without modifiers?

Is there anyway (e.g some command line argument) with which we can tell snort to run and perform detection but without caring for the rule modifiers if there are any ? e.g alert tcp any any -> ...