Posts Tagged: skype resolver


24
May 13

Skype Beta Plugs IP Resolver Privacy Leak

A few months ago, I warned readers that a glaring privacy weakness in voice-over-IP telephony service Skype allows anyone using the network to quickly learn the Internet address of any other Skype user. A new beta version of the popular Microsoft program appears to have nixed that privacy leak with a setting that restricts this capability to connections in your Skype contacts only.

A new privacy feature in Skype Beta 6.5 for Windows and Mac 6.4

A new privacy feature in Skype Beta 6.5 for Windows and Mac 6.4

As I wrote on March 21, 2013,  number of services have emerged to help snoops and ne’er-do-wells exploit this vulnerability to track and harass others online. For example, an online search for “skype resolver” returns dozens of results that point to services (of variable reliability) that allow users to look up the Internet address of any Skype user, just by supplying the target’s Skype account name.

The resolvers can look up the IP address of any Skype user — whether or not that user is in your contacts list or even online at the time of the lookup. What’s more, resolver services frequently are offered in tandem with “booter” or “stresser” services, essentially sites that will launch denial-of-service attacks against a target of your choosing.

Apparently in response to this problem, Microsoft has added a new option to its Skype 6.5 Beta, released April 30, that allows users to allow direct connections to your contacts only. The information tab on this option, found under Skype->Options->Connection, says “When you call someone who isn’t a contact, we’ll keep your IP address hidden.”

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21
Mar 13

Privacy 101: Skype Leaks Your Location

The events of the past week reminded me of a privacy topic I’ve been meaning to revisit: That voice-over-IP telephony service Skype constantly exposes your Internet address to the entire world, and that there are now numerous free and commercial tools that can be used to link Skype user account names to numeric Internet addresses.

A Skype resolver service in action.

A Skype resolver service in action.

The fact that Skype betrays its users’ online location information is hardly news. For example, The Wall Street Journal and other news outlets warned last year about research showing that it was possible to coax Skype into revealing the IP addresses of individual Skype users. But I believe most Skype users still have no clue about this basic privacy weakness.

What’s changed is that over the past year, a number of services have emerged to help snoops and ne’er-do-wells exploit this vulnerability to track and harass others online. For example, an online search for “skype resolver” returns dozens of results that point to services (of variable reliability) that allow users to look up the Internet address of any Skype user, just by supplying the target’s Skype account name.

In the above screen shot, we can see one such service being used to display the IP address most recently used by the Skype account “mailen_support” (this particular account belongs to the tech support contact for Mailien, a Russian pharmacy spam affiliate program by the same name).

A Skype IP resolver service in action.

A Skype IP resolver service in action.

Typically, these Skype resolvers are offered in tandem with “booter” or “stresser” services, online attack tools-for-hire than can be rented to launch denial-of-service attacks (one of these services was used in an attack on this Web site, and on that of Ars Technica last week). The idea being that if you want to knock someone offline but you don’t know their Internet address, you can simply search on Skype to see if they have an account, and then use the resolvers to locate their IP. The resolvers work regardless of any privacy settings the target user may have selected within the Skype program’s configuration panel.

Many of these resolver services offer “blacklisting,” which for a fee will allow users to prevent other users from looking up the IP address attached to a specific Skype account, said Brandon Levene, an independent security researcher.

“It’s basically a protection scheme,” Levene said.

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