The researchers found several properties of Skype that can track not only users’ locations over time, but also their peer-to-peer (P2P) file-sharing activity, according to a summary of the findings on the NYU-Poly web site. Earlier this year, a German researcher found a cross-site scripting flaw in Skype that could allow someone to change an account password without the user’s consent.
“Even when a user blocks callers or connects from behind a Network Address Translation (NAT) —a common type of firewall —it does not prevent the privacy risk,” according to a release from NYU-Poly.
The research team tracked the Skype accounts of about 20 volunteers as well as 10,000 random users over a two-week period and found that callers using VoIP systems can obtain the IP address of another user when establishing a call with that person. The caller can then use commercial geo-IP mapping services to determine the other user’s location and Internet Service Provider (ISP).
The user can also initiate a Skype call, block some packets and quickly terminate the call to obtain an unsuspecting person’s IP address without alerting them with ringing or pop-up windows. Users do not need to be on a contact list, and it can be done even when a user explicitly configures Skype to block calls from non-contacts.
Posted on December 7, 2011 at 12:49 PM •
Good Q&A on clickjacking:
In plain English, clickjacking lets hackers and scammers hide malicious stuff under the cover of the content on a legitimate site. You know what happens when a carjacker takes a car? Well, clickjacking is like that, except that the click is the car.
“Clickjacking” is a stunningly sexy name, but the vulnerability is really just a variant of cross-site scripting. We don’t know how bad it really is, because the details are still being withheld. But the name alone is causing dread.
EDITED TO ADD (10/13): More details.
Posted on October 6, 2008 at 1:45 PM •
CSRF vulnerabilities occur when a website allows an authenticated user to perform a sensitive action but does not verify that the user herself is invoking that action. The key to understanding CSRF attacks is to recognize that websites typically don’t verify that a request came from an authorized user. Instead they verify only that the request came from the browser of an authorized user. Because browsers run code sent by multiple sites, there is a danger that one site will (unbeknownst to the user) send a request to a second site, and the second site will mistakenly think that the user authorized the request.
If a user visits an attacker’s website, the attacker can force the user’s browser to send a request to a page that performs a sensitive action on behalf of the user. The target website sees a request coming from an authenticated user and happily performs some action, whether it was invoked by the user or not. CSRF attacks have been confused with Cross-Site Scripting (XSS) attacks, but they are very different. A site completely protected from XSS is still vulnerable to CSRF attacks if no protections are taken.
Posted on October 6, 2008 at 5:42 AM •
Sidebar photo of Bruce Schneier by Joe MacInnis.