10 August, 2011
- This vulnerability affects: All current versions of Microsoft Visio
- How an attacker exploits it: By enticing one of your users into opening a maliciously crafted Visio document
- Impact: An attacker can execute code, potentially gaining complete control of your users’ computers
- What to do: Deploy the appropriate Visio patches as soon as possible, or let Windows Update do it for you
Microsoft Visio is a very popular diagramming application, which many administrators use to create network diagrams. It also ships with some Office packages.
In a security bulletin released yesterday, Microsoft describes two security vulnerabilities that affect all current versions of Visio. The vulnerabilities differ technically, but share the same scope and impact. They both involve flaws in how Visio parses Visio documents. If an attacker can entice one of your users into opening a specially crafted Visio file (such as .vsd, .vdx, .vst, or .vtx), he could exploit either of these flaws to execute code on that user’s computer with that user’s privileges. If your user has administrative privileges, the attacker could gain complete control of their computer.
Microsoft has released Visio patches to fix this flaw. You should download, test, and deploy the appropriate patches as soon as possible, or let Windows Update do it for you.
For All WatchGuard Users:
If the practice fits your business environment, you can use the HTTP, SMTP, and/or POP3 proxies to block Visio documents by extension (such as .vsd, .vdx, .vst, or .vtx). However, doing so blocks both malicious and legitimate file.
If you would like to use our proxies to block Visio documents, follow the links below for instructions:
- XTM Appliance with WSM 11.x
- Firebox X Edge running 10.x
- Firebox X Core and X Peak running Fireware 10.x
Microsoft has released a fix.
This alert was researched and written by Corey Nachreiner, CISSP.
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