A private security research outfit on Tuesday warned that a "highly critical" vulnerability in the Microsoft Jet Database Engine could be exploited by malicious hackers to hijack a compromised system.
The flaw, which was discovered by HexView Security Research and Assessment, affects fully patched systems with Microsoft Access 2003 and Microsoft Windows XP, including Service Pack 2.
eWEEK.com has confirmed the publication of exploit code for this vulnerability, which carries a "highly critical" rating from independent alerts aggregator Secunia.
Microsoft Jet database is a lightweight database widely used by applications such as Microsoft Office 2000, Office 2003, Access 2000 and Access 2003.
According to an advisory from HexView, the vulnerability is caused due to a memory handling error when parsing database files. This can be exploited to execute arbitrary code by tricking a user into opening a specially crafted ".mdb" file in Microsoft Access.
The problem exists in "msjet40.dll," the main component of the Microsoft Jet Database Engine, which evaluates and carries out requests for data. "HexView noticed multiple occurrences where file data was not validated or improperly validated leading to system crashes, null pointer memory access conditions, and arbitrary code execution," the company said in the alert.
"Sufficient data validation is not performed when msjet40.dll parses the database file. As a result, it is possible to modify database file to cause a code of attackers choice to be launched when MS Jet database is opened," the alert said.
Only software products that utilize "msjet40.dll" are affected.
Microsoft officials did not respond to queries for comment at press time.
HexView said Microsoft was notified of the vulnerability on March 30, 2005, but an acknowledgement only came in the form of an automated reply. No human response was received, according to HexView.
The software giant is expected to release security fixes later Tuesday for eight product flaws as part of its monthly patching cycle.
In the absence of a patch from Microsoft, Secunia recommends that users avoid opening untrusted ".mdb" database files.