March 19, 2018

We need to talk about IDS signatures


The names Snort and Suricata are known to all who work in the field of network security. WAF and IDS are two classes of security systems that analyze network traffic, parse top-level protocols, and signal the presence of malicious or unwanted network activity. Whereas WAF helps web servers detect and avoid attacks targeted only at them, IDS detects attacks in all network traffic.

Many companies install an IDS to control traffic inside the corporate network. The DPI mechanism lets them collect traffic streams, peer inside packets at the IP, HTTP, DCE/RPC, and other levels, and identify both the exploitation of vulnerabilities and network activity by malware.

At the heart of both systems are signature sets used for detecting known attacks, developed by network security experts and companies worldwide.
We at the @attackdetection team also develop signatures to detect network attacks and malicious activity. Later on in the article, we'll discuss a new approach we discovered that disrupts the operation of Suricata IDS systems, and then hides all trace of such activity.

March 13, 2018

How to assemble a GSM phone based on SDR


The smartphones so familiar to most of us contain an entire communication module separate from the main CPU. This module is what makes a "smartphone" a "phone." Regardless of whether the phone's user-facing operating system is Android or iOS, the module usually runs a proprietary closed-source operating system and handles all voice calls, SMS messages, and mobile Internet traffic.

Of course, open-source projects are more interesting to security researchers than closed-source ones. The ability to look under the hood and see how a particular program component works makes it possible to find and fix errors, plus verify that undocumented functionality is not present. As a pleasant bonus, access to source code helps novice developers to learn from colleagues and make contributions of their own.

March 5, 2018

The First Rule of Mobile World Congress Is: You Do Not Show Anyone Your Mobile World Congress Badge


The biggest event of the telecom industry attracted particularly wide media coverage this year: the King of Spain personally arrived in Barcelona for the opening of the annual Mobile World Congress (MWC 2018), which caused a wave of protests by supporters of the region's independence from Madrid. As a result, newspaper front pages and TV channel prime time are all taken by high tech and telecom innovations against the backdrop of protesting crowds. And it is recommended that all participants and visitors to the Congress should not wear a badge outside the venue for greater security.