Feeds

Defend your phone against loose networks? There’s an app for that

Researchers unveil ‘middlebox detection’ software

The Power of One eBook: Top reasons to choose HP BladeSystem

A group of researchers from the University of Michigan has released an Android app designed to defend against a common firewall vulnerability which they say commonly exposes smartphones on cellular networks.

The vulnerability, “off-path TCP sequence number inference”, can allow hijacking of Web pages users are trying to visit. The researchers say that some types of stateful firewalls, designed to drop packets without valid TCP sequence numbers, can be attacked by an insider that’s able to guess TCP sequence numbers of other users, and use this as the basis of a redirection.

The firewalls are common on cellular networks, the researchers say, with as many as 31.5 percent of the networks they tested using the stateful firewalls.

The researchers, Z. Morley Mao (a professor at Michigan) and doctoral student Zhiyun Qian, say that smartphones’ sandbox models can make them vulnerable to having a malware-infected machine inside the firewall read the incoming packet counters from an Android device, and let the attacker know when the sequence numbers advance. A successful attack also depends on having suitable malware on the Android phone, o as to get sequence numbers out of its sandbox.

"An attacker can try to guess at sequence numbers. It's usually hard to get feedback on whether a guessed number is correct, but the firewall middlebox makes this possible," Qian said. "The attacker can try a range of sequence numbers. The firewall will only allow one through if it is in the valid range."

A successful redirection allows the attacker to gain IDs and passwords of users on the same network. The researchers have also published a paper (PDF) describing other attack types. For example, the attacker could use TCP sequence number inference to create a spoofed IP address to perform denial-of-service on another server.

Their app, offered on Google Play, checks the firewall type on a network and alerts the user if it is vulnerable to the attack.

Mao and Qian are presenting their work at the IEEE Symposium on Security and Privacy in San Francisco. ®

Designing a Defense for Mobile Applications

More from The Register

next story
DARPA-derived secure microkernel goes open source tomorrow
Hacker-repelling, drone-protecting code will soon be yours to tweak as you see fit
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
Researcher sat on critical IE bugs for THREE YEARS
VUPEN waited for Pwn2Own cash while IE's sandbox leaked
Four fake Google haxbots hit YOUR WEBSITE every day
Goog the perfect ruse to slip into SEO orfice
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.