Feeds

Skype bug gives attackers access to Mac OS X machines

'Extremely wormable and dangerous'

Choosing a cloud hosting partner with confidence

Mac users running Skype are vulnerable to self-propagating exploits that allow an attacker to gain unfettered system access by sending a specially manipulated attachment in an instant message, a hacker said.

“The long and the short of it is that an attacker needs only to send a victim a message and they can gain remote control of the victim's Mac,” Gordon Maddern of Australian security consultancy Pure Hacking blogged on Friday. “It is extremely wormable and dangerous.”

The vulnerability, which Maddern said isn't present in the Windows or Linux versions of the popular VoIP program, was confirmed by Skype spokeswoman Brianna Reynaud, who said a fix will be rolled out next week. Its disclosure comes the same week that researchers discovered a new crimekit that streamlines the production of Mac-based malware. It also comes as new malware surfaced for Apple's OS X that masquerades as a legitimate antivirus program.

Reynaud said there are no reports that the Skype vulnerability is being actively exploited.

Maddern said he stumbled on the critical flaw by accident.

“About a month ago I was chatting on skype to a colleague about a payload for one of our clients,” he wrote. “Completely by accident, my payload executed in my colleagues skype client. So I decided to test another mac and sent the payload to my girlfriend. She wasn't too happy with me as it also left the her skype unusable for several days.”

He then set out to write proof-of-concept attack code that used payloads borrowed from the Metasploit exploit framework. The result: a Skype exploit that allows him to remotely gain shell access on a targeted Mac. Because it's sent by instant messages, it might be possible to force each infected machines to send the malicious payload to a whole new set of Macs, causing the attack to grow exponentially.

Maddern didn't say what interaction is required on the part of the victim, and he didn't immediately respond to an email seeking clarification. His blog post says he notified Skype of the vulnerability more than a month ago, and that he will withhold specific details until a patch is released to prevent malicious attacks. ®

Update

According to a post on the Skype Security blog that was published a few hours after this story went live, a hotfix for the vulnerability was released in mid April.

“As there were no reports of this vulnerability being exploited in the wild, we did not prompt our users to install this update, as there is another update in the pipeline that will be sent out early next week,” Skype's Adrian Asher wrote.

He added:

This vulnerability, which they blogged about earlier today, is related to a situation when a malicious contact would send a specifically crafted message that could cause Skype for Mac to crash. Note, this message would have to come from someone already in your Skype Contact List, as Skype's default privacy settings will not let you receive messages from people that you have not already authorized, hence the term malicious contact.

The headline in this article was updated to correct the nature of the vulnerability. It remotely gives shell access.

Security for virtualized datacentres

More from The Register

next story
TEEN RAMPAGE: Kids in iPhone 6 'Will it bend' YouTube 'prank'
iPhones bent in Norwich? As if the place wasn't weird enough
Consumers agree to give up first-born child for free Wi-Fi – survey
This Herod network's ace – but crap reception in bullrushes
Crouching tiger, FAST ASLEEP dragon: Smugglers can't shift iPhone 6s
China's grey market reports 'sluggish' sales of Apple mobe
Sea-Me-We 5 construction starts
New sub cable to go live 2016
New EU digi-commish struggles with concepts of net neutrality
Oettinger all about the infrastructure – but not big on substance
PEAK IPV4? Global IPv6 traffic is growing, DDoS dying, says Akamai
First time the cache network has seen drop in use of 32-bit-wide IP addresses
EE coughs to BROKEN data usage metrics BLUNDER that short-changes customers
Carrier apologises for 'inflated' measurements cockup
Comcast: Help, help, FCC. Netflix and pals are EXTORTIONISTS
The others guys are being mean so therefore ... monopoly all good, yeah?
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.
The next step in data security
With recent increased privacy concerns and computers becoming more powerful, the chance of hackers being able to crack smaller-sized RSA keys increases.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
A strategic approach to identity relationship management
ForgeRock commissioned Forrester to evaluate companies’ IAM practices and requirements when it comes to customer-facing scenarios versus employee-facing ones.