#Ms jet database engine Patch#
#Ms jet database engine code#
#Ms jet database engine download#

Many researchers have extensively analyzed the Jet database file structure. To do this we must understand the Jet database file. We investigate the user-provided data of 0x00002300 to understand its purpose. Now we need to determine why the program attempts to write at that location. We know that the program attempts to write out of bounds and we know where the attempt occurs. While tracking the program, we determined the value 0x00002300 comes from the proof-of-concept file group1.

It appears to be an array in which each variable is 4 bytes long and starts at the location edx+574h. From this information, we can guess the type of data that is stored there. Finally, they are added together with an offset of 574 hexadecimal bytes to reference the memory location. Edx is a pointer to memory that we will see again later. The debug information shows that register ecx contains the value 0x00002300. We need to understand how this location is constructed to provide clues to the root cause. Specifically, we can see that the program is using the вЂњesiвЂќ register to write to the location, but that location is not accessible.

By running poc.js through wscript.exe, we can trigger the crash.ДЄs we see in the preceding image, we can review debug information to determine the function that crashes is вЂњmsrd3x40!TblPage::CreateIndexes.вЂќ Furthermore, we can determine that the program is trying to write data and failing.

#Ms jet database engine code#

The proof of concept code contains one JavaScript file (poc.js), which calls a second file (group1). The following diagram provides a high-level view of how the exploit works: The file exploits an index field in the Jet database file format with an unexpectedly large number, resulting in an out-of-bounds write and, ultimately, the preceding crash. The cause of the crash is the maliciously crafted Jet database file. This type of vulnerability indicates that data can be written outside of the intended buffer, resulting in a crash. This vulnerability is an вЂњout-of-bounds write,вЂќ which can be triggered via OLE DB, the API used to access data in many Microsoft applications. The message shows an access violation occurred in the vulnerable DLL. The following error message indicates the vulnerability was successfully triggered: Once the malicious Jet database file is accessed, it calls the vulnerable function in msrd3x40.dll which can lead to exploitation of this vulnerability.ДЄlthough the available proof of concept causes a crash in wscript.exe, any application using this DLL is susceptible to the attack. To exploit this vulnerability, an attacker needs to use social engineering techniques to convince a victim to open a JavaScript file which uses an ADODB connection object to access a malicious Jet Database file. We do not know if the vulnerability is used in any attacks however, the proof of concept code is widely available.

#Ms jet database engine download#

The flaw allows an attacker to execute code to escalate privileges or to download malware. The vulnerability exploits the Microsoft Jet Database Engine, a component used in many Microsoft applications, including Access.

#Ms jet database engine Patch#

We were able to find some issues with the patch and reported that to Microsoft, which resulted in another vulnerability, CVE-2019-0576, which was fixed on (Microsoft Jan 2019 Patch Tuesday). We investigated this flaw at that time to protect our customers. Microsoft released a patch in October 2018.

In September 2018, the Zero Day Initiative published a proof of concept for a vulnerability in MicrosoftвЂ™s Jet Database Engine. By Hardik Shah, Charles McFarland and Thomas Roccia on Jul 30, 2019