Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Mobile Security //

Cellular Network

// // //
09:05 AM
Larry Loeb
Larry Loeb
Larry Loeb

Researchers Show How Attackers Can Crack LTE Data Link Layer

In a paper, researchers show how an attacker with the right equipment can crack the data link layer of an LTE network. It's mostly theoretical, but it shows why upcoming 5G security standards need to be tougher.

A new report by security researchers at Ruhr-University Bochum and New York University Abu Dhabi has shown how the data link layer of the 4G LTE mobile telephony standard can be defeated.

In their paper, entitled "Breaking LTE on Layer Two," the researchers show two passive attacks that can determine many details -- including identity and website fingerprinting -- about the traffic along with an active attack that can change where the traffic ends up.

The snappy name they gave to the active attack is aLTEr. It can carry out DNS spoofing to redirect traffic.

However, the attacks are not something most users will have to concern themselves with right now. While the paper showed the feasibility of the attacks, it required use of an experimental network set up by the researchers that may not translate well into normal use.

(Source: Flickr)
(Source: Flickr)

That setup had some limiting factors.

For instance, the researchers note:

We use a shielding box to prevent our relay from interfering with the commercial network in the licensed spectrum, following ethics guidelines. Further, the shielding box stabilizes the user equipment's (UE) radio connection and prevents non-deterministic behavior of the relay. In other words, the shielding box setup assures that the UE does not connect to any other available cell and the malicious relay does not interfere with itself.

Some might say that the researchers actually stacked the deck to make things work for them.

They also asserted that their results will be real-world possible, even though they did not directly do it: "While we use this to simplify the experimental procedure, the setup is comparable to IMSI catcher [so-called 'Stingray' boxes used by law enforcement -- ed.] attacks when considering the victim's perspective. Such attacks were conducted successfully in real-world environments, i.e., without shielding equipment."

The aLTEr attack "exploits the missing integrity protection of LTE user data to perform a chosen-ciphertext attack," according to the researchers. It depends on a malicious relay acting as a rogue base station towards the user. The implicit assumption here is that the UE will first connect with the rogue station.

See how that UE shielding used in their experimental setup all of a sudden becomes really significant?

Boost your understanding of new cybersecurity approaches at Light Reading's Automating Seamless Security event on October 17 in Chicago! Service providers and enterprise receive FREE passes. All others can save 20% off passes using the code LR20 today!

Second, the relay acts as an unauthenticated user in the commercial network, and must be undetected by that network. Researchers think that by forwarding all messages between the user device and the network, the malicious relay will be undetectable.

However, the underlying problem exploited by aLTEr is that 4G data packets are not integrity-protected by the counter mode (AES-CTR) that is used. Instead, an attacker can intercept packets, alter them, and then relay those modified packets. And here the researchers have made a good point: While the 5G standard does include some stronger encryption, operators may not use it because of the overhead that is necessary to do so and can slow the speed of a network.

The researchers state their goals simply: "We urgently demand the implementation of effective countermeasures in the upcoming 5G specification to assure the security and privacy of future mobile communication."

Related posts:

— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.

Comment  | 
Print  | 
More Insights
Newest First  |  Oldest First  |  Threaded View
I Smell a RAT! New Cybersecurity Threats for the Crypto Industry
David Trepp, Partner, IT Assurance with accounting and advisory firm BPM LLP,  7/9/2021
Attacks on Kaseya Servers Led to Ransomware in Less Than 2 Hours
Robert Lemos, Contributing Writer,  7/7/2021
It's in the Game (but It Shouldn't Be)
Tal Memran, Cybersecurity Expert, CYE,  7/9/2021
Register for Dark Reading Newsletters
White Papers
Current Issue
Everything You Need to Know About DNS Attacks
It's important to understand DNS, potential attacks against it, and the tools and techniques required to defend DNS infrastructure. This report answers all the questions you were afraid to ask. Domain Name Service (DNS) is a critical part of any organization's digital infrastructure, but it's also one of the least understood. DNS is designed to be invisible to business professionals, IT stakeholders, and many security professionals, but DNS's threat surface is large and widely targeted. Attackers are causing a great deal of damage with an array of attacks such as denial of service, DNS cache poisoning, DNS hijackin, DNS tunneling, and DNS dangling. They are using DNS infrastructure to take control of inbound and outbound communications and preventing users from accessing the applications they are looking for. To stop attacks on DNS, security teams need to shore up the organization's security hygiene around DNS infrastructure, implement controls such as DNSSEC, and monitor DNS traffic
Flash Poll
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
PUBLISHED: 2023-05-26
Craft is a CMS for creating custom digital experiences. Cross site scripting (XSS) can be triggered by review volumes. This issue has been fixed in version 4.4.7.
PUBLISHED: 2023-05-26
Django-SES is a drop-in mail backend for Django. The django_ses library implements a mail backend for Django using AWS Simple Email Service. The library exports the `SESEventWebhookView class` intended to receive signed requests from AWS to handle email bounces, subscriptions, etc. These requests ar...
PUBLISHED: 2023-05-26
Highlight is an open source, full-stack monitoring platform. Highlight may record passwords on customer deployments when a password html input is switched to `type="text"` via a javascript "Show Password" button. This differs from the expected behavior which always obfuscates `ty...
PUBLISHED: 2023-05-26
Craft is a CMS for creating custom digital experiences on the web.The platform does not filter input and encode output in Quick Post validation error message, which can deliver an XSS payload. Old CVE fixed the XSS in label HTML but didn’t fix it when clicking save. This issue was...
PUBLISHED: 2023-05-26
GDSDB infinite loop in Wireshark 4.0.0 to 4.0.5 and 3.6.0 to 3.6.13 allows denial of service via packet injection or crafted capture file