Microsoft Investigating Windows VBScript Security Hole

Microsoft released a security advisory Monday describing a zero-day vulnerability involving some older Windows versions and VBScript when used with Internet Explorer.

The vulnerability permits a complicated exploit only on systems using Windows 2000, Windows XP, and Windows Server 2003. Newer Windows versions aren't affected, according to the advisory. To pull off the exploit, users have to be diverted to a malicious Web site, and they have to push the F1 (Help) button on the keyboard while a script is running.

Friday, third-party security firm iSEC Security Research published a proof of concept description of the vulnerability. Microsoft responded Sunday in a blog post by Jerry Bryant, a senior manager with the Microsoft Security Response Center. Microsoft was investigating "new public claims of vulnerability involving the use of VBScript and Windows Help (HLP) files within Internet Explorer," according to Bryant.

The exploit could be triggered by "passing [a] malicious .HLP file to winhlp32," according to iSEC. It would permit an arbitrary command to be run by an attacker. iSEC also pointed to "a stack overflow vulnerability in winhlp32.exe."

The exploit allows a remote code execution attack via a malicious Web page. Microsoft's security advisory says that if "a malicious Web site displayed a specially crafted dialog box and a user pressed the F1 key," then arbitrary code could be executed during that same browser session.

Bryant said that Microsoft has not yet seen any evidence of attacks exploiting this vulnerability. Windows Vista, Windows 7, Windows Server 2008, and Windows Server 2008 R2 are not affected, according to Microsoft.

However, Bryant conceded that an inherent weakness exists involving the use of VBScript and Windows Help files with Internet Explorer.

"Windows Help files are included in a long list of what we refer to as 'unsafe file types'," he wrote in the blog post. "These are file types that are designed to invoke automatic actions during normal use of the files. While they can be very valuable productivity tools, they can also be used by attackers to try and compromise a system."

Microsoft did not appreciate how the vulnerability was reported. Bryant alluded to a need for "responsible disclosure," and the security advisory noted that it "was not responsibly disclosed." However, neither Bryant's note, nor the advisory, mentioned iSEC's proof of concept.

Microsoft may issue a security update, possibly through its monthly patch cycle. In the meantime, Microsoft suggested a workaround by changing Internet Explorer's security option.

"Setting the Internet zone security setting to High protects against this vulnerability by disabling Active Scripting, which is required in order to exploit this vulnerability," the security advisory noted. Microsoft also advised users against hitting the F1 key when prompted to do so by Web sites.

About the Author

Jabulani Leffall is a business consultant and an award-winning journalist whose work has appeared in the Financial Times of London, Investor's Business Daily, The Economist and CFO Magazine, among others. He consulted for Deloitte & Touche LLP and was a business and world affairs commentator on ABC and CNN.

Featured

  • DreamBox Math

    Discovery Education Announces Updates to Experience, DreamBox Math

    K-12 learning solution provider Discovery Education has announced enhancements to its Discovery Education Experience and DreamBox Math products, designed to create a more personalized, engaging learning experience for students.

  • abstract pattern of cybersecurity, ai and cloud imagery

    Report Identifies Malicious Use of AI in Cloud-Based Cyber Threats

    A recent report from OpenAI identifies the misuse of artificial intelligence in cybercrime, social engineering, and influence operations, particularly those targeting or operating through cloud infrastructure. In "Disrupting Malicious Uses of AI: June 2025," the company outlines how threat actors are weaponizing large language models for malicious ends — and how OpenAI is pushing back.

  • digital dashboard featuring a shield icon, graphs, a world map, and network nodes

    IBM Launches Agentic AI Governance and Security Platform

    IBM has introduced a new software stack for enterprise IT teams tasked with managing the complex governance and security challenges posed by autonomous AI systems.

  • laptop and fish hook

    Security Researchers Identify Generative AI 'Vishing' Attack

    A new report from researchers at Ontinue's Cyber Defense Center has identified a complex, multi-stage cyber attack that leveraged social engineering, remote access tools, and signed binaries to infiltrate and persist within a target network.