Monday, 15 August 2016 09:05

Linux TCP flaw fix likely in next stable release


A patch to fix a weakness in the transmission control protocol used in the Linux kernel since 2012, which could lead to remote hijacking of Internet connections, is available in the public stable queue tree and is likely to be included in the next stable release.

The last stable release of the kernel, version 4.6.6, was on 10 August.

The flaw was discovered by researchers at the University of California, Riverside, and does not require anyone to be using Linux to be vulnerable as a large proportion of Internet servers run the operating system. It was publicised on 9 August in the US.

Data is broken up into packets for transmission on the Internet and the sequence numbers of these packets can be used by malicious attackers to track users' online activity, terminate connections with others and inject material into their communications.

Web Analytics
But given that there are nearly four billion random sequences, guessing them is very difficult.

The UCR researchers found a vulnerability, or a side channel as they dubbed it, in the TCP stack used by Linux which allows attackers to guess the sequence numbers if they know the IP address of two parties communicating with each other.

The patch increases the rate of challenge acknowledgement signals from 100 to 1000. It also adds randomisation so that an attacker will need to undertake a large number of probes before he/she can hijack sessions.

In the interim, one fix recommended by California-based sysadmin Rick Moen is to use sysctl to increase the setting in /proc/sys/net/ipv4/tcp_challenge_ack_limit to 999999999.

Subscribe to ITWIRE UPDATE Newsletter here


The much awaited iTWire Shop is now open to our readers.

Visit the iTWire Shop, a leading destination for stylish accessories, gear & gadgets, lifestyle products and everyday portable office essentials, drones, zoom lenses for smartphones, software and online training.

PLUS Big Brands include: Apple, Lenovo, LG, Samsung, Sennheiser and many more.

Products available for any country.

We hope you enjoy and find value in the much anticipated iTWire Shop.



iTWire TV offers a unique value to the Tech Sector by providing a range of video interviews, news, views and reviews, and also provides the opportunity for vendors to promote your company and your marketing messages.

We work with you to develop the message and conduct the interview or product review in a safe and collaborative way. Unlike other Tech YouTube channels, we create a story around your message and post that on the homepage of ITWire, linking to your message.

In addition, your interview post message can be displayed in up to 7 different post displays on our the site to drive traffic and readers to your video content and downloads. This can be a significant Lead Generation opportunity for your business.

We also provide 3 videos in one recording/sitting if you require so that you have a series of videos to promote to your customers. Your sales team can add your emails to sales collateral and to the footer of their sales and marketing emails.

See the latest in Tech News, Views, Interviews, Reviews, Product Promos and Events. Plus funny videos from our readers and customers.


Sam Varghese

Sam Varghese has been writing for iTWire since 2006, a year after the site came into existence. For nearly a decade thereafter, he wrote mostly about free and open source software, based on his own use of this genre of software. Since May 2016, he has been writing across many areas of technology. He has been a journalist for nearly 40 years in India (Indian Express and Deccan Herald), the UAE (Khaleej Times) and Australia (Daily Commercial News (now defunct) and The Age). His personal blog is titled Irregular Expression.

Share News tips for the iTWire Journalists? Your tip will be anonymous




Guest Opinion

Guest Reviews

Guest Research

Guest Research & Case Studies

Channel News