Visual Studio 6.0 Buffer Overflow Vulnerability

Bug Discovered by Kozan
Credits to ATmaCA
Web: www.spyinstructors.com
Mail: kozan@spyinstructors.com

Affected Vendor:

Microsoft (www.microsoft.com)


Affected Products:

Microsoft Visual Studio 6.0 (with latest Service Pack 6)
Microsoft Development Environment 6.0 (SP6) (Microsoft Visual InterDev 6.0)


Vulnerability Details:

A Buffer Overflow Vulnerability is exists for the following file formats of affected product.


Visual Studio Database Project File (.dbp)
Visual Studio Solution (.sln)



The vulnerability is caused due to a boundary error within the handling of a ".dbp" file (.sln files are also affected) that contains an overly long string in the "DataProject" field. This can be exploited to cause a stack-based buffer overflow and allows arbitrary code execution when a malicious ".dbp" file is opened.
A specially crafted project file can overwrite a stack based buffer allowing for fully EIP register control and code execution and compromise user's system.



An example .dbp file:

# Microsoft Developer Studio Project File - Database Project
Begin DataProject = "ProjectName"
End


Carriage return and line feed (0x0d and 0x0a) characters and some others (0x00 ...) can not be used in project name variable.


An example .dbp file which overwrites EIP register:

# Microsoft Developer Studio Project File - Database Project
Begin DataProject = "Project1AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAXXXX
AAAA123456AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
End

The lenght must be 384 bytes long. Otherwise other registers will be overwriten differently and exploitation method will be chanced. So 384 bytes long length is the most suitable way.

In this example when file is opened:

XXXX (0x58585858) characters will overwrite EIP.
And 123456AAAA... (3132333435364141... in hex) bytes will be on ESP.

So an attacker could create a malicious .dbp project file which includes a payload which on ESP and EIP should point to this shellcode with a loaded moduls jmp esp or call esp opcodes.


PoC:

The local path length of the dbp file changes the arragement of malformed data. So, exploit has to re-align the data for total path length.

Copy the following file as c:\deneme\Project1.dbp

http://www.spyinstructors.com/kozan/poc/vuln.dbp