SafeUM
Home Blog Services Download Help About Recharge

Axarhöfði 14, 110 Reykjavik, Iceland

Iceland - 2015
SafeUM
Blog
Services
Download
Help
About
Recharge
Menu
Archive
TOP Security!
21 May 2015

Logjam attack exposes data passed over TLS connections

Computer scientists have identified weaknesses in the way popular cryptographic algorithm Diffie-Hellman key exchange is deployed – notably, they discovered an attack that could enable the reading and modifying of data passed over TLS connections.

All servers that support DHE_EXPORT ciphers, as well as all modern browsers, are affected, according to a website advisory. A Skyhigh blog post indicated that 575 cloud services are vulnerable, and that the average enterprise is using 71 vulnerable cloud services.

The attack – referred to as Logjam – can be used by a man-in-the-middle (MITM) attacker to downgrade TLS connections to 512-bit export-grade cryptography that is weaker and easier to crack, thus enabling the reading and modifying of data, the website advisory explained. Ken Westin, senior security analyst at Tripwire, noted in a Wednesday blog post that the issue has been around longer than two decades, adding it affects HTTPS, SSH, IPsec, SMTPS and protocols that rely on TLS, making it very widespread.

The Logjam attack is similar to the FREAK attack that was identified in March, the website advisory said, except it attacks Diffie-Hellman key exchange as opposed to RSA key exchange, and is the result of a flaw in TLS protocol and is not an implementation vulnerability.

“The population of affected sites is slightly lower than for FREAK,” Bill Weinberg, senior director of Open Source Strategy with Black Duck Software, told in a message. “8.4 percent of the top million web domains are reported vulnerable and 3.4 percent of HTTPS sites, as well as email servers using SMTP with several standard types of authentication.” Weinberg also noted, “Like FREAK, Logjam is the result of encryption export restrictions implemented by the U.S. Government twenty years ago to protect then-strategic encryption tech.”

Rapid7 Security Engineering Manager Tod Beardsley, in a statement emailed to SCMagazine.com on Wednesday, said, “The only two groups really in a position to take advantage of this vulnerability are 1) criminals on coffee shop Wi-Fi networks; and 2) state actors who already control a huge chunk of the local Internet – [the] usual rogues gallery of internet criminals are not really a risk here.”

Currently the issue has been addressed in Internet Explorer. Richard Barnes, cryptographic engineering manager with Mozilla, told SCMagazine.com in a Wednesday email that a fix in Firefox is expected to be released in a few days. A Google spokesperson told that a fix in the stable version of Chrome will be available in the coming weeks, and that a fix in Chrome Canary should be live in a day or two.

However, coming up with a fix was not easy and making it so browsers reject keys with fewer than 1,024 bits could result in as many as 20,000 websites becoming inaccessible. Those that run a web or mail server should disable support for export cipher suites and generate a unique 2048-bit Diffie Hellman group, and those using SSH should upgrade server and client installations to the most recent version of OpenSSH, according to the website advisory.

Sysadmins and developers should use updated TLS libraries and reject Diffie-Hellman groups smaller than 1024-bit, and vulnerable browser users should remain on the lookout for updates as fixes are deployed, the advisory added. The security scientists published a research paper with further details, in which they examine evidence from leaked Edward Snowden documents that suggested the NSA has been exploiting the capability to decrypt VPN traffic.

Tags:
Logjam TLS information leaks MITM HTTPS
Source:
SC Magazine
2516
Other NEWS
3 Jul 2020 safeum news imgage An encrypted messaging service has been infiltrated by police
4 May 2020 safeum news imgage Two-Factor Authentication ​What Is It and Why You Should Use It
12 Dec 2019 safeum news imgage Encryption is under threat - this is how it affects you
4 Nov 2019 safeum news imgage Should Big Decisions Be Based on Data or Your Intuition?
7 Jun 2018 safeum news imgage VPNFilter malware infecting 500,000 devices is worse than we thought
4 Jun 2018 safeum news imgage Hackers target Booking.com in criminal bid to steal hundreds of thousands from customers
1 Jun 2018 safeum news imgage Operator of World's Top Internet Hub Sues German Spy Agency
30 May 2018 safeum news imgage US says North Korea behind malware attacks
29 May 2018 safeum news imgage Facebook and Google targeted as first GDPR complaints filed
25 May 2018 safeum news imgage A new reason to not buy these cheap Android devices
24 May 2018 safeum news imgage Flaws in smart pet devices, apps could come back to bite owners
23 May 2018 safeum news imgage Google sued for 'clandestine tracking' of 4.4m UK iPhone users' browsing data
21 May 2018 safeum news imgage LocationSmart reportedly leaked phone location data onto the web
18 May 2018 safeum news imgage The SEC created its own scammy ICO to teach investors a lesson
17 May 2018 safeum news imgage Thieves suck millions out of Mexican banks in transfer heist
All news
SafeUM
Confidential Terms of Use Our technologies Company
Follow us
Download
SafeUM © Safe Universal Messenger

Axarhöfði 14,
110 Reykjavik, Iceland

Iceland - 2015