Rapid7

module

Firebird Relational Database CNCT Group Number Buffer Overflow

Disclosed
Jan 31, 2013
Created
May 30, 2018

Description

This module exploits a vulnerability in Firebird SQL Server. A specially
crafted packet can be sent which will overwrite a pointer allowing the attacker to
control where data is read from. Shortly, following the controlled read, the
pointer is called resulting in code execution.

The vulnerability exists with a group number extracted from the CNCT information,
which is sent by the client, and whose size is not properly checked.

This module uses an existing call to memcpy, just prior to the vulnerable code,
which allows a small amount of data to be written to the stack. A two-phases
stack pivot allows to execute the ROP chain which ultimately is used to execute
VirtualAlloc and bypass DEP.

Author

Spencer McIntyre

Platform

Windows

Architectures

x86

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/windows/misc/fb_cnct_group
msf exploit(fb_cnct_group) > show targets
...targets...
msf exploit(fb_cnct_group) > set TARGET < target-id >
msf exploit(fb_cnct_group) > show options
...show and set options...
msf exploit(fb_cnct_group) > exploit

Title
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