Expert disclosed an unpatched zero-day flaw in all supported versions of Microsoft Windows

Pierluigi Paganini September 21, 2018

A security researcher from Trend Micro Security Research team disclosed an unpatched zero-day vulnerability in all supported versions of Microsoft Windows.

The researcher Lucas Leong of the Trend Micro Security Research team publicly disclosed an unpatched zero-day vulnerability in all supported versions of Microsoft Windows.

The flaw is an out-of-bounds (OOB) write in the JET Database Engine that could be exploited by a remote attacker to execute arbitrary code on the vulnerable systems.

The zero-day vulnerability has received CVSS score of 6.8 and resides in the management of indexes in JET. An attacker can use specially crafted data in a database file to trigger a write past the end of an allocated buffer.

Experts highlighted that the exploitation of the flaw requires user interaction, the attackers have to trick victims into opening a malicious file that would trigger the bug.

The specially crafted file has to contain data stored in the JET database format.

The expert disclosed the flaw through the Trend Micro’s Zero Day Initiative (ZDI) on Thursday, the issue affects the Microsoft JET Database Engine.

Lucas Leong reported the flaw to Microsoft in early May 2018, he expected the flaw would have been fixed with the September 2018 Patch Tuesday set of security updates, but Microsoft did not fix it.

“Today, we are releasing additional information regarding a bug report that has exceeded the 120-day disclosure timeline” reads the blog post published by ZDI.

“An out-of-bounds (OOB) write in the Microsoft JET Database Engine that could allow remote code execution was initially reported to Microsoft on May 8, 2018. An attacker could leverage this vulnerability to execute code under the context of the current process, however it does require user interaction since the target would need to open a malicious file. As of today, this bug remains unpatched.”

According to the ZDI’s disclosure policy, details on the vulnerability could be released 120 days after the vendor was notified on the issue, even if the flaw was still unpatched.

ZDI also published the proof-of-concept (PoC) exploit code for the vulnerability.

Windows zero-day

Microsoft confirmed the existence of the flaw in Windows 7, but experts at ZDI believes the issue affects all supported Windows version.

“Our investigation has confirmed this vulnerability exists in Windows 7, but we believe that all supported Windows version are impacted by this bug, including server editions. You can view our advisory here.” ZDI concludes.

“Microsoft continues to work on a patch for this vulnerability, and we hope to see it in the regularly scheduled October patch release. In the absence of a patch, the only salient mitigation strategy is to exercise caution and not open files from untrusted sources.” 

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Pierluigi Paganini

(Security Affairs – zero-day, Windows)

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