Use Cases related to the targeting opportunists attacker class. This class represents a more targeted focused group of Opportunists, they don’t scan and probe the internet and stop as soon as they stumble across something interesting. They target one organisation in an opportunistic way. Meaning they will mass scan a particular organisation continuously looking for weak spots.
Emerging Threats SIG 2002677 create an alert if the user agent contain the string “Nikto/xxxx” is detected (where xxx is representing the version of Nikto2) in destination of HTTP, or HTTPS. An alert will be sent after seeing 5 occurrences of events per 60 second, then will ignore any additional events during the 60 seconds.
Nikto2 is used, normally, to evaluate to security of Web servers. If you detect these kind of activities, you should add the attacker IP address to an “Aggressive Attacker” list for furthers trends and correlations.
Nikto2 web scanner SIG 2002677 1 Week events activitiesNikto2 web scanner SIG 2002677 1 month events activitiesNikto2 web scanner SIG 2002677 1 year events activities
We have compile a list of more of 5 000 user name how have been used to try to brute force login our HoneyNet servers. This list is updated every day.
Emerging Threats SIG 2001219 create an alert if we have 5 destination port 22/TCP connexions during the interval of 120 seconds. If we see, for example, 10 connexions during the interval of 120 seconds, 2 alerts will be triggered. This SIG could be used to detect SSH Brute Force Attack.
Emerging Threats SIG 2006546 create an alert if the content of the packet in destination of port 22/TCP contain “SSH-” and “libssh”. In addition the alert is triggered if we detect 5 connexions during the interval of 30 seconds. If we see, for example, 10 connexions during the interval of 30 seconds, only 1 alert will be triggered. This SIG could be used to detect SSH Brute Force Attack, but based on strict recognition of tools how are using “libssh”.
Emerging Threats SIG 2006345 create an alert if the content of the packet in destination of port 22/TCP contain “SSH-” and “libssh”. In addition the alert is triggered if we detect 1 connexion during the interval of 30 seconds. If we see, for example, 10 connexions during the interval of 30 seconds, only 1 alert will be triggered. This SIG could be used to detect SSH fingerprinting, but based on strict recognition of tools how are using “libssh”. This SIG is not useful for SSH Brute Force Attack recognition due to the limit type threshold.
In parallel you could correlate theses alerts with your firewall logs and / or SSH daemon logs, to create a real correlated alert. But still the attacker is not logged in your system, these alerts should not have a high priority level, cause most of time these scans are done by bots. Maybe you could add the attacker IP address in a “Suspicious Attacker” list for furthers trends and correlations activities.
Another operation you could do, is to compare the username provided from the SSH brute forcing dictionary with yours existing SSH usernames. If your username is present into the dictionary, we recommend you to change it.
24 hours SIG 2001219 events activities1 week SIG 2001219 events activities1 Month SIG 2001219 events activitiesOne year SIG 2001219 events activities1 Month TOP 10 source IPs for SIG 2001219TOP 20 source countries for SIG 2001219
24 hours 500 destination port events1 week destination port 500 event1 month destination port 500 events1 year destination port 500 eventssource ports repartition for destination port 500source countries repartition for destination port 500
