Rootkits

Rootkits are "malicious software", just like viruses and worms. Rootkits are special because they are almost impossible to detect.

The name "Rootkit" was derived from the superuser name in UNIX, called "root". This root user has all rights on a system, just like the Windows Administrator has. By the way, rootkits are a problem of all operating systems, including Windows.

Rootkits and other malicious software can create backdoors in systems. Using this backdoor, hackers can penetrate the system to use it, to damage it (erasing or destroying data) or to use the system for attacks on other systems.

Rootkits are very hard to detect because they not only install malicious software, but they also install software that replace system commands. An example is the UNIX/Linux commando 'ls -l'. This command is used to print a list of files on the screen:

$ ls -l
total 72
drwxr-xr-x 3 slaan slaan 4096 2006-09-14 11:02 BACKUP
drwxr-xr-x 9 slaan slaan 4096 2006-09-16 13:52 google-earth
-rwxrwxrwx 1 slaan slaan 150 2006-10-02 19:50 maliciouscode.exe
drwxr-xr-x 8 slaan slaan 4096 2006-05-05 09:44 Murdoc_development
drwxrwxrwt 7 slaan slaan 4096 2006-09-10 13:54 My Virtual Machines
drwxr-xr-x 2 slaan slaan 4096 2006-09-15 08:45 scripts
drwxr-xr-x 11 slaan slaan 4096 2006-09-25 15:35 uapplications
drwxr-xr-x 2 slaan slaan 4096 2006-09-12 21:42 vmware

A rootkit could install a new version of 'ls'. This way the malicious code becomes invisible:

$ ls -l
total 72
drwxr-xr-x 3 slaan slaan 4096 2006-09-14 11:02 BACKUP
drwxr-xr-x 9 slaan slaan 4096 2006-09-16 13:52 google-earth
drwxr-xr-x 8 slaan slaan 4096 2006-05-05 09:44 Murdoc_development
drwxrwxrwt 7 slaan slaan 4096 2006-09-10 13:54 My Virtual Machines
drwxr-xr-x 2 slaan slaan 4096 2006-09-15 08:45 scripts
drwxr-xr-x 11 slaan slaan 4096 2006-09-25 15:35 uapplications
drwxr-xr-x 2 slaan slaan 4096 2006-09-12 21:42 vmware

To prevent this to be noticed, incorrect information about the 'ls' command itself is showed by the patched 'ls' command. This hides files with incorrect sizes. If necessary, rootkits could even change the kernel to make it show incorrect values!

There are two ways to prevent rootkits from being installed: 

  1. Using virus detection, the installation of rootkits can be avoided;
  2. Using Host-based-IDS (Intruder Detection Systems) technology changes to the system can be detected.

Both methods are very delicate however: Circumventing virus scanners can be done already and IDS systems can be misguided by rootkits, just like it misguides other applications and commands.

In 2005 rootkits made the news when it was uncovered that record company Sony/BMG installed rootkits, using their music CD's, to secretly install copy protection software. Eventually, it cost Sony much more than it gained. Client's trust was damaged which cost a lot more than a few illegally copied CD's.


This entry was posted on Friday 08 December 2006

Earlier articles

The cloud is as insecure as its configuration

Infrastructure as code

My Book

DevOps for infrastructure

Infrastructure as a Service (IaaS)

(Hyper) Converged Infrastructure

Object storage

Software Defined Networking (SDN) and Network Function Virtualization (NFV)

Software Defined Storage (SDS)

What's the point of using Docker containers?

Identity and Access Management

Using user profiles to determine infrastructure load

Public wireless networks

Supercomputer architecture

Desktop virtualization

Stakeholder management

x86 platform architecture

Midrange systems architecture

Mainframe Architecture

Software Defined Data Center - SDDC

The Virtualization Model

What are concurrent users?

Performance and availability monitoring in levels

UX/UI has no business rules

Technical debt: a time related issue

Solution shaping workshops

Architecture life cycle

Project managers and architects

Using ArchiMate for describing infrastructures

Kruchten’s 4+1 views for solution architecture

The SEI stack of solution architecture frameworks

TOGAF and infrastructure architecture

The Zachman framework

An introduction to architecture frameworks

How to handle a Distributed Denial of Service (DDoS) attack

Architecture Principles

Views and viewpoints explained

Stakeholders and their concerns

Skills of a solution architect architect

Solution architects versus enterprise architects

Definition of IT Architecture

What is Big Data?

How to make your IT "Greener"

What is Cloud computing and IaaS?

Purchasing of IT infrastructure technologies and services

IDS/IPS systems

IP Protocol (IPv4) classes and subnets

Infrastructure Architecture - Course materials

Introduction to Bring Your Own Device (BYOD)

IT Infrastructure Architecture model

Fire prevention in the datacenter

Where to build your datacenter

Availability - Fall-back, hot site, warm site

Reliabilty of infrastructure components

Human factors in availability of systems

Business Continuity Management (BCM) and Disaster Recovery Plan (DRP)

Performance - Design for use

Performance concepts - Load balancing

Performance concepts - Scaling

Performance concept - Caching

Perceived performance

Ethical hacking

The first computers

Open group ITAC /Open CA Certification

Sjaak Laan


Recommended links

Ruth Malan
Gaudi site
Esther Barthel's site on virtualization
Eltjo Poort's site on architecture


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The postings on this site are my opinions and do not necessarily represent CGI’s strategies, views or opinions.

 

Copyright Sjaak Laan