# Nessus Scanner Crashes Logstash Syslog Inputs

**URL:** <https://discuss.elastic.co/t/nessus-scanner-crashes-logstash-syslog-inputs/41328>\
**Category:** Logstash\
**Created:** [February 9, 2016, 11:23pm UTC](https://discuss.elastic.co/t/nessus-scanner-crashes-logstash-syslog-inputs/41328 "2016-02-09T23:23:12Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![arizonawayfarer](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/arizonawayfarer/32/44846_2.png) [@arizonawayfarer](https://discuss.elastic.co/u/arizonawayfarer)\
**Post date:** [February 9, 2016, 11:23pm UTC](https://discuss.elastic.co/t/nessus-scanner-crashes-logstash-syslog-inputs/41328/1 "2016-02-09T23:23:12Z")

</div>

Hi everyone,

I'm not sure where/how to file a bug report - but we have a nessus scanner running on our network that sends garbage to tcp/udp ports it discovers to find exploits.

When this happens, it kills the logstash listeners with no real descriptive error:

```
{:timestamp=>"2016-02-08T05:05:07.472000-0700", :message=>"syslog listener died", :protocol=>:udp, :address=>"XXX.XXX.XXX.XXX:514", :exception=>#<SocketError: recvfrom: name or service not known>, :backtrace=>["C:/logstash-2.1.1/vendor/bundle/jruby/1.9/gems/logstash-input-syslog-2.0.2/lib/logstash/inputs/syslog.rb:138:in `udp_listener'", "C:/logstash-2.1.1/vendor/bundle/jruby/1.9/gems/logstash-input-syslog-2.0.2/lib/logstash/inputs/syslog.rb:117:in `server'", "C:/logstash-2.1.1/vendor/bundle/jruby/1.9/gems/logstash-input-syslog-2.0.2/lib/logstash/inputs/syslog.rb:97:in `run'"], :level=>:warn}
{:timestamp=>"2016-02-08T05:05:07.472000-0700", :message=>"syslog listener died", :protocol=>:udp, :address=>"XXX.XXX.XXX.XXX:515", :exception=>#<SocketError: recvfrom: name or service not known>, :backtrace=>["C:/logstash-2.1.1/vendor/bundle/jruby/1.9/gems/logstash-input-syslog-2.0.2/lib/logstash/inputs/syslog.rb:138:in `udp_listener'", "C:/logstash-2.1.1/vendor/bundle/jruby/1.9/gems/logstash-input-syslog-2.0.2/lib/logstash/inputs/syslog.rb:117:in `server'", "C:/logstash-2.1.1/vendor/bundle/jruby/1.9/gems/logstash-input-syslog-2.0.2/lib/logstash/inputs/syslog.rb:97:in `run'"], :level=>:warn}

```

I managed to grab a couple of strings that nessus is sending to the sockets, and it looks like it's sending unicode chars in an attempt to run arbitrary code. I don't believe that these particular strings are what's killing the listeners, and are only examples of the types of garbage that nessus is writing to the sockets. I would be happy to help track this down, if I can get some guidance on figuring out exactly what is making the listeners die.

```
\u0002lp\n
\u0004\fTOB\n
\u0004nessus-1454933147 \n

```

Input config:

```
input {
	syslog {
		host => "XXX.XXX.XXX.XXX"
		codec => plain { charset => "CP1252" }
		port => 514
		type => "syslog1"
	}
  
 	syslog {
		host => "XXX.XXX.XXX.XXX"
		port => 515
		type => "syslog2"
	}
}
```

---

<div class="post-metadata">

**Author:** ![magnusbaeck](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/magnusbaeck/32/44943_2.png) [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)\
**Post date:** [February 10, 2016, 6:53am UTC](https://discuss.elastic.co/t/nessus-scanner-crashes-logstash-syslog-inputs/41328/2 "2016-02-10T06:53:16Z")

</div>

There have been a number of similar reports (e.g. the issue below) and I don't think what you see has much to do with the payload that Nessus sends. The Logstash team should try to get to the bottom of this.

> <https://github.com/logstash-plugins/logstash-input-syslog/issues/18>

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 6, 2017, 5:12am UTC](https://discuss.elastic.co/t/nessus-scanner-crashes-logstash-syslog-inputs/41328/3 "2017-07-06T05:12:19Z")

</div>