I am not a big Windows user, so this one applies less to me, but having a calendar reminder on the Wednesday after patch Tuesday to make sure that the patch Tuesday updates are applied makes some sense. As you may have dozens of programs patched each week, it is easier to just reboot the system.
Same idea: Patches will often require a restart of the particular software patched. So I make it a habit to restart my browser in the morning. Chrome has a useful indicator warning, but not everybody "sees" it. Some systems may not be stable enough for this to matter, but I find that if you keep your browser open all the time (as many of us do by default), and never close it, browser updates do not get applied.
There are some of the items that I am considering, and well PLEASE suggest yours: Restart your browser at least once a day The calendar would be more targeted at home users and enthusiasts, certainly not at enterprises, but they may develop their own based on some of these ideas. Lately, I have been toying with the idea of creating an "infosec calendar" with activities to perform regularly. Xavier Mertens ISC Handler - Freelance Cyber Security Consultant I checked the other domains against, but they're not registered yet. The script tries to contact them in a loop until a valid server is found.Īt this time, the initial domain points to a Google Cloud. The string is Base64 encoded, and a common TLD (“.top”) is added. "hee","xu1","hs0","jd5","mqf" | % ĭomains are generated by concatenating a small string with the current date (“%y%m%V” returns the current year, month, and week number). Once registered to the C2 server, it enters a loop and waits for commands from the C2. It contains the second stage, Base64-encoded. I found a simple malicious PowerShell script that implements a backdoor. Attackers just register a few domain names and can change them very quickly. An alternative is to generate a lot of domains and loop across them to find an available C2 server. The idea is to generate domain names periodically and use them during the defined period. So that means that only the ICMP packets are displayed:ĭGA (“Domain Generation Algorithm") is a popular tactic used by malware to make connections with their C2 more stealthy and difficult to block. So that means that only the TCP SYN packets are displayed:ĭisplay filter "ip.src#2 = 192.168.10.10" filters out all IP packets on the second layer that match ip.src = 192.168.10.10. Where layer is a number.ĭisplay filter "ip.src#1 = 192.168.10.10" filters out all IP packets on the first layer that match ip.src = 192.168.10.10. The solution brought with the new syntax, is that one can specify explicitly the protocol stack layer that should be matched, like this: ip.src#layer. It shows the TCP SYN packets because ip.src matches 192.168.10.10, and it shows the ICMP packets because they contain a field ip.src that also matches 192.168.10.10. So these ICMP packets have 2 ip.src fields: one for the outher IP packet and one for the IP packet contained in the ICMP packet (that is contained in the outher IP packet).Īnd that is why the display filter is showing all packets. Why is that? Because the ICMP packets embed the IP packets that caused the error: But although that display filter is applied, I still see the ICMP packets coming from 192.168.10.1. So I only want to see packets that come from 192.168.10.10. I use the following display filter: ip.src = 192.168.10.10
This happens 3 times (because the TCP stack tries 2 retransmissions and then gives up). Take the following packet capture, it shows failed attempts to establish a TCP connection: 192.168.10.10 sends a TCP SYN packet to 192.168.10.1, and this is followed by a "reply", 192.168.10.1 sending an ICMP packet (Destination unreachable) to 192.168.10.10. But let me first explain what the problem is, and then we can talk about the solution that the new syntax brings Specifying a protocol stack layer is one of the new syntax features. The release of Wireshark 4.0.0 brings many new features, especially for the display filter syntax.