Risk
7/8/2013
11:48 AM
50%
50%

Encrypted IM Tool Vulnerable To Eavesdropping

Bugs in instant messaging encryption tool Cryptocat left users' group chats vulnerable to eavesdropping for over a year, says security researcher.

Even so, the developers said they'd revamped their messaging to would-be users. "We've added a new, more visible warning about Cryptocat's experimental status to our website!" the group tweeted Sunday. Likewise, the website where the software may be downloaded sports the following warning: "Cryptocat is not a magic bullet. You should never trust any piece of software with your life, and Cryptocat is no exception."

Thomas acknowledged that the developers' fix corrected the problem his DecryptoCat tool exploits. "For Cryptocat version 2.0.42 this will take 1,000 computer-years to generate [cracked keys], 500 computer-years on average to use, and 40 petabytes to store," he said. "So the only ones capable of doing this are large companies and governments."

Is Cryptocat now safe to use? In fact, Thomas said his bug report wasn't meant to be exhaustive, and warned against relying on the application for encrypted communications. "I'm sure there are plenty of bugs and other bad crypto in other parts because I only looked at random generation and found a bug, at public key algorithm and found a bug, and quickly looked where random is used and found something scary, and random (BigInt.randBigInt) used in two-party messaging and found a bug," he said.

The exploitable Cryptocat vulnerabilities are notable, given that interest in using encrypted communications tools has been growing in the wake of leaks by former National Security Agency (NSA) contractor Edward Snowden, who revealed the existence of numerous NSA data and metadata-interception programs.

But ensuring that communications can't be intercepted depends in large part on the applications not including exploitable vulnerabilities or bugs. For example, Bruce Schneier, chief security technology officer of BT, Monday detailed four techniques for protecting communications against snooping: use vulnerability-free applications, choose secure passwords, manage those passwords securely and know the threat you're facing.

Although Schneier's advice pertained to securing email, it also applies to chat -- and it's notable that the first tip is to use applications that don't include vulnerabilities. His reasoning is simple: No matter how great the cryptography used by an application, if someone wants to intercept messages sent using that application, they're going to first see if "breaking the engineering" might suffice. In the case of Cryptocat, prior to the patch, that would have been the case.

Then again, according to leaked NSA docs, the agency is legally allowed to retain encrypted communications indefinitely, meaning that simply by using an application such as Cryptocat, people might already be putting themselves at greater risk of having their communications intercepted and studied. Thus, anyone who used a vulnerable version of Cryptocat might have had their encrypted communications stored. With Thomas' bug information in hand, decrypting those messages would now be a trivial task.

Previous
2 of 2
Next
Comment  | 
Print  | 
More Insights
Register for Dark Reading Newsletters
White Papers
Cartoon
Current Issue
Flash Poll
Video
Slideshows
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2015-0750
Published: 2015-05-22
The administrative web interface in Cisco Hosted Collaboration Solution (HCS) 10.6(1) and earlier allows remote authenticated users to execute arbitrary commands via crafted input to unspecified fields, aka Bug ID CSCut02786.

CVE-2012-1978
Published: 2015-05-21
Multiple cross-site request forgery (CSRF) vulnerabilities in Simple PHP Agenda 2.2.8 and earlier allow remote attackers to hijack the authentication of administrators for requests that (1) add an administrator via a request to auth/process.php, (2) delete an administrator via a request to auth/admi...

CVE-2015-0741
Published: 2015-05-21
Multiple cross-site request forgery (CSRF) vulnerabilities in Cisco Prime Central for Hosted Collaboration Solution (PC4HCS) 10.6(1) and earlier allow remote attackers to hijack the authentication of arbitrary users, aka Bug ID CSCut04596.

CVE-2015-0742
Published: 2015-05-21
The Protocol Independent Multicast (PIM) application in Cisco Adaptive Security Appliance (ASA) Software 9.2(0.0), 9.2(0.104), 9.2(3.1), 9.2(3.4), 9.3(1.105), 9.3(2.100), 9.4(0.115), 100.13(0.21), 100.13(20.3), 100.13(21.9), and 100.14(1.1) does not properly implement multicast-forwarding registrati...

CVE-2015-0746
Published: 2015-05-21
The REST API in Cisco Access Control Server (ACS) 5.5(0.46.2) allows remote attackers to cause a denial of service (API outage) by sending many requests, aka Bug ID CSCut62022.

Dark Reading Radio
Archived Dark Reading Radio
Join security and risk expert John Pironti and Dark Reading Editor-in-Chief Tim Wilson for a live online discussion of the sea-changing shift in security strategy and the many ways it is affecting IT and business.