Posts Tagged: UC Berkeley’s International Computer Science Institute


21
Nov 18

USPS Site Exposed Data on 60 Million Users

U.S. Postal Service just fixed a security weakness that allowed anyone who has an account at usps.com to view account details for some 60 million other users, and in some cases to modify account details on their behalf.

Image: USPS.com

KrebsOnSecurity was contacted last week by a researcher who discovered the problem, but who asked to remain anonymous. The researcher said he informed the USPS about his finding more than a year ago yet never received a response. After confirming his findings, this author contacted the USPS, which promptly addressed the issue.

The problem stemmed from an authentication weakness in a USPS Web component known as an “application program interface,” or API — basically, a set of tools defining how various parts of an online application such as databases and Web pages should interact with one another.

The API in question was tied to a Postal Service initiative called “Informed Visibility,” which according to the USPS is designed to let businesses, advertisers and other bulk mail senders “make better business decisions by providing them with access to near real-time tracking data” about mail campaigns and packages.

In addition to exposing near real-time data about packages and mail being sent by USPS commercial customers, the flaw let any logged-in usps.com user query the system for account details belonging to any other users, such as email address, username, user ID, account number, street address, phone number, authorized users, mailing campaign data and other information.

Many of the API’s features accepted “wildcard” search parameters, meaning they could be made to return all records for a given data set without the need to search for specific terms. No special hacking tools were needed to pull this data, other than knowledge of how to view and modify data elements processed by a regular Web browser like Chrome or Firefox.

A USPS brochure advertising the features and benefits of Informed Visibility.

In cases where multiple accounts shared a common data element — such as a street address — using the API to search for one specific data element often brought up multiple records. For example, a search on the email addresses for readers who volunteered to help with this research turned up multiple accounts when those users had more than one user signed up at the same physical address.

“This is not good,” said one anonymous reader who volunteered to help with this research, after viewing a cut-and-paste of his USPS account details looked up via his email address. “Especially since we moved due to being threatened by a neighbor.”

Nicholas Weaver, a researcher at the International Computer Science Institute and lecturer at UC Berkeley, said the API should have validated that the account making the request had permission to read the data requested.

“This is not even Information Security 101, this is Information Security 1, which is to implement access control,” Weaver said. “It seems like the only access control they had in place was that you were logged in at all. And if you can access other peoples’ data because they aren’t enforcing access controls on reading that data, it’s catastrophically bad and I’m willing to bet they’re not enforcing controls on writing to that data as well.”

A cursory review by KrebsOnSecurity indicates the promiscuous API let any user request account changes for any other user, such as email address, phone number or other key details.

Fortunately, the USPS appears to have included a validation step to prevent unauthorized changes — at least with some data fields. Attempts to modify the email address associated with my USPS account via the API prompted a confirmation message sent to the email address tied to that account (which required clicking a link in the email to complete the change).

It does not appear USPS account passwords were exposed via this API, although KrebsOnSecurity conducted only a very brief and limited review of the API’s rather broad functionality before reporting the issue to the USPS. The API at issue resides here; a copy of the API prior to its modification on Nov. 20 by the USPS is available here as a text file. Continue reading →


17
Aug 15

Stress-Testing the Booter Services, Financially

The past few years have witnessed a rapid proliferation of cheap, Web-based services that troublemakers can hire to knock virtually any person or site offline for hours on end. Such services succeed partly because they’ve enabled users to pay for attacks with PayPal. But a collaborative effort by PayPal and security researchers has made it far more difficult for these services to transact with their would-be customers.

Image:

Image:

By offering a low-cost, shared distributed denial-of-service (DDoS) attack infrastructure, these so-called “booter” and “stresser” services have attracted thousands of malicious customers and are responsible for hundreds of thousands of attacks per year. Indeed, KrebsOnSecurity has repeatedly been targeted in fairly high-volume attacks from booter services — most notably a service run by the Lizard Squad band of miscreants who took responsibility for sidelining the Microsoft xBox and Sony Playstation on Christmas Day 2014.

For more than two months in the summer 2014, researchers with George Mason University, UC Berkeley’s International Computer Science Institute, and the University of Maryland began following the money, posing as buyers of nearly two dozen booter services in a bid to discover the PayPal accounts that booter services were using to accept payments. In response to their investigations, PayPal began seizing booter service PayPal accounts and balances, effectively launching their own preemptive denial-of-service attacks against the payment infrastructure for these services.

PayPal will initially limit reported merchant accounts that are found to violate its terms of service (turns out, accepting payments for abusive services is a no-no). Once an account is limited, the merchant cannot withdraw or spend any of the funds in their account. This results in the loss of funds in these accounts at the time of freezing, and potentially additional losses due to opportunity costs the proprietors incur while establishing a new account. In addition, PayPal performed their own investigation to identify additional booter domains and limited accounts linked to these domains as well.

The efforts of the research team apparently brought some big-time disruption for nearly two-dozen of the top booter services. The researchers said that within a day or two following their interventions, they saw the percentage of active booters quickly dropping from 70 to 80 percent to around 50 percent, and continuing to decrease to a low of around 10 percent that were still active.

ppintervention

While some of the booter services went out of business shortly thereafter, more than a half-dozen shifted to accepting payments via Bitcoin (although the researchers found that this dramatically cut down on the services’ overall number of active customers). Once the target intervention began, they found the average lifespan of an account dropped to around 3.5 days, with many booters’ PayPal accounts only averaging around two days before they were no longer used again.

The researchers also corroborated the outages by monitoring hacker forums where the services were marketed, chronicling complaints from angry customers and booter service operators who were inconvenienced by the disruption (see screen shot galley below).

A booter service proprietor advertising his wares on the forum Hackforums complains about Paypal repeatedly limiting his account.

A booter service proprietor advertising his wares on the forum Hackforums complains about Paypal repeatedly limiting his account.

Another booter seller on Hackforums whinges about PayPal limiting the account he uses to accept attack payments from customers.

Another booter seller on Hackforums whinges about PayPal limiting the account he uses to accept attack payments from customers.

"It's a shame PayPal had to shut us down several times causing us to take money out of our own pocket to purchase servers, hosting and more," says this now-defunct booter service to its former customers.

“It’s a shame PayPal had to shut us down several times causing us to take money out of our own pocket to purchase servers, hosting and more,” says this now-defunct booter service to its former customers.

Deadlyboot went dead after the PayPal interventions. So sad.

Deadlyboot went dead after the PayPal interventions. So sad.

Daily attacks from Infected Stresser dropped off precipitously following the researchers' work.

Daily attacks from Infected Stresser dropped off precipitously following the researchers’ work.

As I’ve noted in past stories on booter service proprietors I’ve tracked down here in the United States, many of these service owners and operators are kids operating within easy reach of U.S. law enforcement. Based on the aggregated geo-location information provided by PayPal, the researchers found that over 44% of the customer and merchant PayPal accounts associated with booters are potentially owned by someone in the United States. Continue reading →