Hackers exploit latest Microsoft zero-day bug

Microsoft raises warning as attacks exploit ASP.Net flaw, urges admins to apply workaround

Microsoft has warned users that hackers are exploiting the unpatched bug in ASP.Net to hijack encrypted Web sessions.

In a Monday update to a previously-published security advisory , Microsoft said that it was seeing "limited, active attacks at this time."

Symantec, which has a massive global network of sensors and honey trap-like systems to detect and capture exploits, said it had not seen any attacks, however.

The vulnerability exists in all versions of ASP.Net, the company's Web application framework used to craft millions of sites and applications, and lets attackers access Web applications with full administrator rights; decrypt session cookies or other encrypted data on a remote server; and access and snatch files from a site or Web application that relies on ASP.Net.

Microsoft acknowledged the flaw last Friday, the same day that a pair of researchers demonstrated how the "oracle padding" bug can be exploited by force-feeding cipher text to an ASP.Net application and noting the returned error messages it returns.

The company again promised to patch the vulnerability, but like last week, did not set a delivery date for the fix.

"We will be releasing a patch on Windows Update, so all machines will get it," said Scott Guthrie, the Microsoft executive who runs the ASP.Net development team.

The next regularly-scheduled security updates will ship 12 October, a little less than three weeks from today.

Occasionally Microsoft issues emergency patches -- called "out-of-band" updates -- to tackle problems, almost always after attacks appear.

Until the company releases a fix, Guthrie continued to urge Web site and application developers to plug the hole with a temporary workaround that involves editing the "web.config" file.

SharePoint Server 2007 and SharePoint 2010 are also vulnerable to ASP.Net attacks, said Microsoft. The SharePoint team has published different web.config editing instructions for its high-profile, highly-profitable collaboration software.

Microsoft wasn't downplaying the threat to Web sites and applications. "The publicly disclosed exploit can be used against all types of ASP.NET applications," Guthrie said in a FAQ he posted Monday.

"All sites that use ASP.NET are affected by this vulnerability," echoed Kevin Brown, an engineer with the Microsoft Security Response Center.

The MSRC also took its usual shot at researchers who publicly disclose bugs in its products before a patch is ready. In an entry to the group's blog , spokesman Dave Forstrom cited "coordinated vulnerability disclosure," a term Microsoft coined last summer to describe how it wants outside researchers to behave.

"We fundamentally believe, and history has shown, that once vulnerability details are released publicly, the probability of exploitation rises significantly," Forstrom said. "Without coordination in place to provide a security update or proper guidance, risk to customers is greatly amplified."

Join the newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags symantecMicrosoftsecurityWindowssoftwareoperating systems

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Gregg Keizer

Computerworld (US)
Show Comments

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Sarah Ieroianni

Brother QL-820NWB Professional Label Printer

The print quality also does not disappoint, it’s clear, bold, doesn’t smudge and the text is perfectly sized.

Ratchada Dunn

Sharp PN-40TC1 Huddle Board

The Huddle Board’s built in program; Sharp Touch Viewing software allows us to easily manipulate and edit our documents (jpegs and PDFs) all at the same time on the dashboard.

George Khoury

Sharp PN-40TC1 Huddle Board

The biggest perks for me would be that it comes with easy to use and comprehensive programs that make the collaboration process a whole lot more intuitive and organic

David Coyle

Brother PocketJet PJ-773 A4 Portable Thermal Printer

I rate the printer as a 5 out of 5 stars as it has been able to fit seamlessly into my busy and mobile lifestyle.

Kurt Hegetschweiler

Brother PocketJet PJ-773 A4 Portable Thermal Printer

It’s perfect for mobile workers. Just take it out — it’s small enough to sit anywhere — turn it on, load a sheet of paper, and start printing.

Matthew Stivala

HP OfficeJet 250 Mobile Printer

The HP OfficeJet 250 Mobile Printer is a great device that fits perfectly into my fast paced and mobile lifestyle. My first impression of the printer itself was how incredibly compact and sleek the device was.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?