Category Archives: Security

DNS Sinkhole Setup : Your defense against Bot net controllers

According to statistics published in csoonline.com cyber crimes damages will hit 6 trillion by 2021 and 6 billion people target ( 75% of projected 8 billion population).  As the access to network is increasing,  hacking and committing cyber crime has become as easy as sending a email with malware link and its clicking by unsuspecting victims.

A botnet consists of a  number of  compromised hosts  controlled by botnet controller managed by third parties .  Bot net constitutes a major security threat and used to deploy malware, steal sensitive data, orchestrate DDoS attack.  Once systems inside a network are compromised by installing malware it becomes very difficult to detect as the theft of data and sources of DDoS is orchestrated from within the network.

DNS sink hole is a process to identify the bot net master hosting malware software servers and assign the dns record of these hosts to localhost, non-existing or unused ip address . A  valid ip is not returned for these host resolution and the infected host never connects to the bot net master server.

In order to understand how DNS Sink hole work we need to understand the bot net structure and its organization.

 How a bot network is organized and activated ?

The initial part involves getting access to inside corporate network.  This can be achieved in many ways like using brute force method to crack the passwords and encrypted data and other approach is rather simple, involving sending a link in email and betting on the chances that some users will click the link and deploy malware on their computers.

Share

KRACK – Key Reinstallation Attacks on WPA2 Protocol

Introduction

KRACK is a security flaw with WPA2  security and it allows to  compromise wireless WPA security  by forcing nonce reuse .

This is not an issue related to passwords but the protocol used by WPA and impacts pretty much all devices which uses wi-fi connection like phone, computers, wi-fi routers are impacted.

Share

Linux PIE/stack corruption (CVE-2017-1000253) Bug and Security Vulnerability

About CVE-2017-1000253 Bug:

This issue is related to the Linux kernel loaded Executable and Linkable Format (ELF) executables. If an ELF application was built as Position Independent Executable (PIE), the loader can allow part of that application’s data segment to map over the memory area reserved for its stack.
It  can cause memory corruption and may allow an unprivileged local user to gain privileged access using Set owner User ID (SUID) or privileged flawed PIE binary.

Share

netstat – 10 Most common usage with examples

netstat is a command line utility in Unix, Linux and Unix like systems to show information about

  • network connections,
  • routing tables,
  • interface statistics,
  • mas-querade connections
  • multicast memberships

By default, netstat displays a list of open sockets of all configured address families , tcp , udp etc.
netstat provide very extensive network details and here are the top netstat usage with different options to get you the just the information you need.

Share

SHA-1 Collision – Insecurity of SHA-1 exposed by Google

SHA-1 is widely used in applications like SSL, SSH, TLS, IPsec PGP, S/MIME to protect the sensitive information.

Google has demonstrated that SHA-1 Collision is possible and two files can have the same SHA-1 hash. This means that system can be manipulated by presenting it with manipulated data with same hash as good data.

Share

MongoDB Ransom Attacks Hit 27000 Systems

MongoDB Ransom Attacks has hit 27,000 Systems in few hours from 12000 impacted servers .

Most of the mongoDB installations are exposed to exploites due to poor default access controls for super users .

Hackers are accessing  MongoDB databaases and then copy and delete data from database running in default, unsecure configuration. In return of data administrators are being asked to pay ransom money by bitcoins.

Share

HeartBleed bug : Frequently Asked questions

heartbleed

What Exactly is HeartBleed bug ?
This bug allows hackers to reads sensitive data from the memory of victim host in 64 k chunks. The memory can have user names , passwords , decrypted information or certificates & keys or other confidential information.

Share

Site Hacked with Pharmacy Spammy Content on search listings

Got a email* today today that adminschoice.com searches on google.com are resulting in pharmacy spammy urls and contents. It took around three hours to find out what is happening and fixing it. Finally the site should be free of spam now. It may take a while to update google index entries but redirect is not happening any more.

Share

ssh Without Password in Few Simple Steps

How to configure passwordless ssh & sftp access in Unix & Linux systems? Follow these simple steps with examples with a basic troubleshooting section at the end. sftp uses underlying ssh access for authentication and after you establish passwordless ssh access you will have passwordless sftp access a s well.

This a real life example of configuring passwordless access for two users . The user ‘web’ in this case needs a secure password less access to another user james in a server ‘devserver’
.

Share

Securing Solaris

secure solaris

Protect your system from internal & external security vulnerabilities

Introduction
Solaris security broadly falls under two groups – one is where the system is accessible using local area network/vlan and it has to be secured against unauthorized access. Second is system is accessible over the Internet to a number of persons and it has to be protected against unauthorized access using network or security loopholes.
This document details some of the focus areas for security and provides suggestions to make it strong.

Share