Microsoft patches Passport

Microsoft patched a hole in its .Net Passport identity management service last night after a security researcher disclosed a potentially serious flaw that could enable attackers to hijack Passport accounts.

The vulnerability was in the code for a "Secret Question" feature that helped users who had forgotten their Passport password, according to a message posted by Victor Manuel Alvarez Castro, who identified himself as a security consultant.

Some Passport accounts that were created before the Secret Question feature was implemented in August 1999 contained "bad data" in the Secret Question field, according to Jeff Jones, senior director of Trustworthy Computing Security at Microsoft.

That data enabled knowledgeable attackers to circumvent the Secret Question feature and reset the password for another Passport user's account, he said.

Attackers needed to know both the e-mail address and home country of the account owner. In the case of U.S.-based accounts, an attacker also needed the state and zip code of the account owner, Jones said.

Microsoft would not comment on how many Passport user accounts were affected, but Jones characterized the number as a "small fraction" of the subset of accounts that were created before August 1999 for which no secret question had been established.

After verifying the problem Monday, Microsoft temporarily suspended the password update feature that relied on the Secret Question for all its Passport users, Jones said.

The Redmond, Washington, company patched the errant code Monday evening so that the bad data could not be used to circumvent the Secret Question requirement, then updated the Passport service overnight, Jones said.

Microsoft does not have any evidence that the vulnerability was exploited, Jones said.

Customers whose Passport accounts were affected by the problem should still be able to log in to the service. Those individuals can overwrite the bad data by setting up a valid Secret Question, Jones said.

Customers can also use an e-mail-based update feature to update their password, he said.

The company did not receive any word from Castro prior to the public disclosure and first learned of the flaw when it was posted to software security newsgroups, he said.

Microsoft encourages security researchers to report problems to Microsoft before disclosing them to the public, Jones said.

"We try to develop relationships with professionals out there and encourage responsible reporting. I don’t know this guy, but he didn’t follow responsible reporting rules," he said.

Join the newsletter!


Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Paul Roberts

IDG News Service
Show Comments

Brand Post

Most Popular Reviews

Latest Articles


PCW Evaluation Team

Luke Hill


I need power and lots of it. As a Front End Web developer anything less just won’t cut it which is why the MSI GT75 is an outstanding laptop for me. It’s a sleek and futuristic looking, high quality, beast that has a touch of sci-fi flare about it.

Emily Tyson

MSI GE63 Raider

If you’re looking to invest in your next work horse laptop for work or home use, you can’t go wrong with the MSI GE63.

Laura Johnston

MSI GS65 Stealth Thin

If you can afford the price tag, it is well worth the money. It out performs any other laptop I have tried for gaming, and the transportable design and incredible display also make it ideal for work.

Andrew Teoh

Brother MFC-L9570CDW Multifunction Printer

Touch screen visibility and operation was great and easy to navigate. Each menu and sub-menu was in an understandable order and category

Louise Coady

Brother MFC-L9570CDW Multifunction Printer

The printer was convenient, produced clear and vibrant images and was very easy to use

Edwina Hargreaves

WD My Cloud Home

I would recommend this device for families and small businesses who want one safe place to store all their important digital content and a way to easily share it with friends, family, business partners, or customers.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?