Old Excel paves way for targeted attacks

 

Connecting state and local government leaders

New and still-unpatched vulnerability exists in older versions of the spreadsheet program.

A recently unearthed and still-unpatched vulnerability in older versions of the Microsoft Office Excel spreadsheet program might be more trouble than initially expected, according to security experts.

"Overall, the risk is a little higher" than most people might realize, said James Shewmaker, who runs security consultant firm Bluenotch and works as an instructor for the SANS Institute. "Once more knowledge of the vulnerability gets out in the open this could be a pretty big problem pretty soon."

The vulnerability exists in Excel 2003 Service Pack 2, Excel Viewer 2003, Excel 2002, Excel 2000 and Excel 2004 for the Macintosh computer.

Newer versions of Excel, such as Excel 2007, Excel 2008 for Mac and even Excel 2003 with Service Pack 3 are not affected.

Microsoft has not issued a patch for the vulnerability, but indicated that it is working on one when it publicized the threat last week.

Even though this vulnerability affects only older versions of Excel, it could pose a major risk for federal agencies, as many still run older, often unpatched versions of the software, Shewmaker noted. And because Excel spreadsheets are so widely used, it is doubtful that they would be blocked altogether by organizations.

According to an advisory, Microsoft is investigating how the vulnerability may have been used to compromise customer systems, though the company has not released any details of the vulnerability itself.

Microsoft stressed that thus far the vulnerability has only been used in targeted attacks, attacks where someone has sent specially crafted content to a specific computer user in order to infiltrate that system. Customers who believe they've been attacked should contact Microsoft, the company said.

For the vulnerability to be used in an attack scenario, the victim must open an Excel document. If the user has administrative rights on that machine, the exploit would allow a remote user to then take over control of that computer. An infected Excel file could be sent by e-mail, or the user could also be lured, via an e-mail or instant message link, to an infected file on a Web site.

Microsoft warns users with these versions of Excel to not open Excel files (which may come with .xls, .xlt and .xla extensions) from untrusted sources. The company also recommends running files from unknown sources through the Microsoft Office Isolated Conversion Environment, which converts Office documents into the newer Microsoft Office formats, and could block malicious files in the process.

To exploit the vulnerability, the malicious party would create a malformed header in the document. The header information would corrupt system memory in a way that could allow a remote user to execute code on that machine.

If the user has full administrative privileges, the attacker could take full control of the computer. But even if the user only has user rights, that system could still be harnessed as a node in a botnet, said John Strand, a consultant with security engineering company Argotek, and an instructor for the SANS Institute as well.

Strand noted that this vulnerability is one of a growing number of zero-day attacks centered on Microsoft Office. Zero-day attacks are exploits that target vulnerabilities that have been made known before that software can be patched. The wording of the Microsoft advisory indicates that the company was made aware of this vulnerability from an outside source.

"We used to talk all the time about if zero-day exploits are happening, well now they are," Strand said. He added that even networks connected to the Internet could be at risk, as Office documents could be copied onto these networks by users.

NEXT STORY: Wyatt Kash | TSA: Lessons ignored

X
This website uses cookies to enhance user experience and to analyze performance and traffic on our website. We also share information about your use of our site with our social media, advertising and analytics partners. Learn More / Do Not Sell My Personal Information
Accept Cookies
X
Cookie Preferences Cookie List

Do Not Sell My Personal Information

When you visit our website, we store cookies on your browser to collect information. The information collected might relate to you, your preferences or your device, and is mostly used to make the site work as you expect it to and to provide a more personalized web experience. However, you can choose not to allow certain types of cookies, which may impact your experience of the site and the services we are able to offer. Click on the different category headings to find out more and change our default settings according to your preference. You cannot opt-out of our First Party Strictly Necessary Cookies as they are deployed in order to ensure the proper functioning of our website (such as prompting the cookie banner and remembering your settings, to log into your account, to redirect you when you log out, etc.). For more information about the First and Third Party Cookies used please follow this link.

Allow All Cookies

Manage Consent Preferences

Strictly Necessary Cookies - Always Active

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Sale of Personal Data, Targeting & Social Media Cookies

Under the California Consumer Privacy Act, you have the right to opt-out of the sale of your personal information to third parties. These cookies collect information for analytics and to personalize your experience with targeted ads. You may exercise your right to opt out of the sale of personal information by using this toggle switch. If you opt out we will not be able to offer you personalised ads and will not hand over your personal information to any third parties. Additionally, you may contact our legal department for further clarification about your rights as a California consumer by using this Exercise My Rights link

If you have enabled privacy controls on your browser (such as a plugin), we have to take that as a valid request to opt-out. Therefore we would not be able to track your activity through the web. This may affect our ability to personalize ads according to your preferences.

Targeting cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites. They do not store directly personal information, but are based on uniquely identifying your browser and internet device. If you do not allow these cookies, you will experience less targeted advertising.

Social media cookies are set by a range of social media services that we have added to the site to enable you to share our content with your friends and networks. They are capable of tracking your browser across other sites and building up a profile of your interests. This may impact the content and messages you see on other websites you visit. If you do not allow these cookies you may not be able to use or see these sharing tools.

If you want to opt out of all of our lead reports and lists, please submit a privacy request at our Do Not Sell page.

Save Settings
Cookie Preferences Cookie List

Cookie List

A cookie is a small piece of data (text file) that a website – when visited by a user – asks your browser to store on your device in order to remember information about you, such as your language preference or login information. Those cookies are set by us and called first-party cookies. We also use third-party cookies – which are cookies from a domain different than the domain of the website you are visiting – for our advertising and marketing efforts. More specifically, we use cookies and other tracking technologies for the following purposes:

Strictly Necessary Cookies

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Functional Cookies

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Performance Cookies

We do not allow you to opt-out of our certain cookies, as they are necessary to ensure the proper functioning of our website (such as prompting our cookie banner and remembering your privacy choices) and/or to monitor site performance. These cookies are not used in a way that constitutes a “sale” of your data under the CCPA. You can set your browser to block or alert you about these cookies, but some parts of the site will not work as intended if you do so. You can usually find these settings in the Options or Preferences menu of your browser. Visit www.allaboutcookies.org to learn more.

Sale of Personal Data

We also use cookies to personalize your experience on our websites, including by determining the most relevant content and advertisements to show you, and to monitor site traffic and performance, so that we may improve our websites and your experience. You may opt out of our use of such cookies (and the associated “sale” of your Personal Information) by using this toggle switch. You will still see some advertising, regardless of your selection. Because we do not track you across different devices, browsers and GEMG properties, your selection will take effect only on this browser, this device and this website.

Social Media Cookies

We also use cookies to personalize your experience on our websites, including by determining the most relevant content and advertisements to show you, and to monitor site traffic and performance, so that we may improve our websites and your experience. You may opt out of our use of such cookies (and the associated “sale” of your Personal Information) by using this toggle switch. You will still see some advertising, regardless of your selection. Because we do not track you across different devices, browsers and GEMG properties, your selection will take effect only on this browser, this device and this website.

Targeting Cookies

We also use cookies to personalize your experience on our websites, including by determining the most relevant content and advertisements to show you, and to monitor site traffic and performance, so that we may improve our websites and your experience. You may opt out of our use of such cookies (and the associated “sale” of your Personal Information) by using this toggle switch. You will still see some advertising, regardless of your selection. Because we do not track you across different devices, browsers and GEMG properties, your selection will take effect only on this browser, this device and this website.