Filemaker Login Bypass and Privilege Escalation
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[ADVISORY INFORMATION]
Title: Filemaker Login Bypass and Privilege Escalation
Discovery date: 19/10/2014
Release date: 19/10/2014
Vendor Homepage: www.filemaker.com
Version: Filemaker Pro 13.0v3 - FileMaker Pro Advanced 12.0v4
Credits: Giuseppe D'Amore (http://it.linkedin.com/pub/giuseppe-d-amore/69/37/66b)
[VULNERABILITY INFORMATION]
Class: Authentication Bypass and Privilege Escalation
Category: Desktop Application
Severity: High
CVSS v2 Vector: 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C
[AFFECTED PRODUCTS]
This security vulnerability affects:
* FileMaker Pro 13.0v3 - FileMaker Pro Advanced 12.0v4
[VULNERABILITY DETAILS]
There is a obvious vulnerability of FileMaker that allow access to the local FM-based database file:
On DBEngine dll, there is a function called MatchPasswordData:
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5BB8D53A C68424 74020000 >MOV BYTE PTR SS:[ESP+274],0
5BB8D542 FF15 D437D25B CALL DWORD PTR DS:[<&Support.??1PasswordHash@Draco@@QAE@XZ>] <-- Compute the password's hash.
5BB8D548 8B8C24 6C020000 MOV ECX,DWORD PTR SS:[ESP+26C]
5BB8D54F 5F POP EDI
5BB8D550 5E POP ESI
5BB8D551 8AC3 MOV AL,BL <-- if AL is 0 then you are not authenticated else if AL is 1 you are authenticated,
so simply by changing a single bit you are able to bypass the login,
also if your username is Admin, you can obtain a privilege escalation and full permissions on DB.
5BB8D553 64:890D 00000000 MOV DWORD PTR FS:[0],ECX
5BB8D55A 5B POP EBX
5BB8D55B 8BE5 MOV ESP,EBP
5BB8D55D 5D POP EBP
5BB8D55E C2 0400 RETN 4
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it doesn't matter if your desktop or mobile application is developed in a "secure manner", your confidential data on the database can be accessed.
[DISCLOSURE TIME-LINE]
* 19/10/2014 - Public disclosure and simultaneously initial vendor contact.
[DISCLAIMER]
The author is not responsible for the misuse of the information provided in
this security advisory. The advisory is a service to the professional security
community. There are NO WARRANTIES with regard to this information. Any
application or distribution of this information constitutes acceptance AS IS,
at the user's own risk. This information is subject to change without notice.
