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Mac OS X libxpc MITM Privilege Escalation

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Mac OS X libxpc MITM Privilege Escalation

Disclosed
03/15/2018
Created
03/19/2019

Description

This module exploits a vulnerablity in libxpc on macOS <= 10.13.3 The task_set_special_port API allows callers to overwrite their bootstrap port, which is used to communicate with launchd. This port is inherited across forks: child processes will use the same bootstrap port as the parent. By overwriting the bootstrap port and forking a child processes, we can now gain a MitM position between our child and launchd. To gain root we target the sudo binary and intercept its communication with opendirectoryd, which is used by sudo to verify credentials. We modify the replies from opendirectoryd to make it look like our password was valid.

Author(s)

  • saelo

Platform

OSX

Architectures

x64

Development

References

Module Options

To display the available options, load the module within the Metasploit console and run the commands 'show options' or 'show advanced':

msf > use exploit/osx/local/libxpc_mitm_ssudo
msf exploit(libxpc_mitm_ssudo) > show targets
    ...targets...
msf exploit(libxpc_mitm_ssudo) > set TARGET < target-id >
msf exploit(libxpc_mitm_ssudo) > show options
    ...show and set options...
msf exploit(libxpc_mitm_ssudo) > exploit

Time is precious, so I don’t want to do something manually that I can automate. Leveraging the Metasploit Framework when automating any task keeps us from having to re-create the wheel as we can use the existing libraries and focus our efforts where it matters.

– Jim O’Gorman | President, Offensive Security

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