Identify the vulnerability

We'll cover several common ways a site can be compromised. Hopefully, one of these vulnerabilities will either apply to your site or will shed light on additional possibilities.

Please be aware that vulnerability scanners differ from antivirus scanners. Vulnerability scanners can be far more invasive and have greater potential to cause unwanted damage to your site. Please follow all directions, such as backing up your site, before running the scanner.

Potential vulnerabilities

Potential vulnerabilities to investigate include:

Virus-infected administrator’s computer

On an administrator’s virus-infected computer, the hacker may have installed spyware to record the site admin’s keystrokes.

• Check for viruses on administrator’s systems. We recommend running several reputable antivirus scanners, or AV scanners, on every computer used by an administrator to log in to the site. Since new malware infections are constantly being designed to evade scanners, this action isn't a foolproof method of virus detection. Since AV scanners might report false positives, running several scanners can provide more data points to determining whether a vulnerability exists. Also consider scanning both your webserver and all devices used to update or post to the site, just to be safe.
  • If the AV scanner detects spyware, a virus, trojan horse, or any suspicious program, investigate the site’s server logs to check for activity by the administrator who owns the infected computer.
  • Log files may have been altered by the hacker. If not, correlating the administrator’s username with suspicious commands in the log file is further evidence that a virus on an administrator’s system caused the site to be vulnerable.

Weak or reused passwords

Cracking a weak password can be relatively easy for hackers, and it provides them direct access to your server. Strong passwords have a combination of letters and numbers, punctuation, no words or slang that might be found in a dictionary. Passwords should only be used for one application, not reused throughout the web. When passwords are reused, it only takes one security breach-on one application for a hacker to find the login-and-password then attempt to reuse it elsewhere.

• In the server log, check for undesirable activity, such as multiple login attempts for an administrator or an administrator making unexpected commands. Make note of when the suspicious activity occurred because understanding when the hack first took place helps determine what backups may still be clean.

Out-of-date software

Check that your server(s) have installed the latest version of the operating system, content management system, blogging platform, applications, plugins, etc.

• Research (perhaps through a web search) all installed software to determine if your version contains a security advisory. If so, the possibility that outdated software caused your site to be vulnerable is quite likely.
• As a best practice, always aim to keep your servers' software up to date, regardless of whether outdated software resulted in vulnerability issues this time.

4. Permissive coding practices, such as open redirects and SQL injections

Open redirects

Open redirects are coded with the intention for the URL structure to allow the addition of another URL so users can reach a useful file or webpage on the site. For example:

http://example.com/page.php?url=http://example.com/good-file.pdf

or

http://example.com/page.php?url=<malware-attack-site>

• If your site is abused by open redirects, you likely noticed the message in Search Console provided example URLs that included open redirects to an undesirable destination.
• To prevent open redirects in the future, check if "allow open redirects" is turned on by default in your software, whether your code can prohibit off-domain redirects, or if you can sign the redirect so that only those with properly hashed URLs and the cryptographic signature can be redirected.

SQL injections

SQL injections occur when a hacker is able to add rogue commands to user input fields executed by your database. SQL injections update records in your database with unwanted spam or malware content, or they dump valuable data to output for the hacker. If your site uses a database, and especially if you were infected with the malware type SQL injection, it’s possible that your site was compromised by a SQL injection.

• Login to the database server and look for suspicious content in the database, such as otherwise regular text fields that now show iframes or scripts.
• For suspicious values, check that the user input is validated and properly escaped or perhaps strongly typed so they can't be executed as code. if user input isn't checked before database processing, SQL injection may be a root-cause vulnerability on your site.

SQL CREATE INDEX Statement

SQL CREATE INDEX Statement

The CREATE INDEX statement is used to create indexes in tables.

Indexes are used to retrieve data from the database very fast. The users cannot see the indexes, they are just used to speed up searches/queries.

Note: Updating a table with indexes takes more time than updating a table without (because the indexes also need an update). So, only create indexes on columns that will be frequently searched against.

CREATE INDEX Syntax

Creates an index on a table. Duplicate values are allowed:

CREATE INDEX index_name
ON table_name (column1, column2, ...);

CREATE UNIQUE INDEX Syntax

Creates a unique index on a table. Duplicate values are not allowed:

CREATE UNIQUE INDEX index_name
ON table_name (column1, column2, ...);

Note: The syntax for creating indexes varies among different databases. Therefore: Check the syntax for creating indexes in your database.

---

CREATE INDEX Example

The SQL statement below creates an index named "idx_lastname" on the "LastName" column in the "Persons" table:

CREATE INDEX idx_lastname
ON Persons (LastName);

If you want to create an index on a combination of columns, you can list the column names within the parentheses, separated by commas:

CREATE INDEX idx_pname
ON Persons (LastName, FirstName);

---

DROP INDEX Statement

The DROP INDEX statement is used to delete an index in a table.

MS Access:

DROP INDEX index_name ON table_name;

SQL Server:

DROP INDEX table_name.index_name;

DB2/Oracle:

DROP INDEX index_name;

MySQL:

ALTER TABLE table_nameDROP INDEX index_name;

SQL Injection

Overview

A SQL injection attack consists of insertion or "injection" of a SQL query via the input data from the client to the application. A successful SQL injection exploit can read sensitive data from the database, modify database data (Insert/Update/Delete), execute administration operations on the database (such as shutdown the DBMS), recover the content of a given file present on the DBMS file system and in some cases issue commands to the operating system. SQL injection attacks are a type of injection attack, in which SQL commands are injected into data-plane input in order to effect the execution of predefined SQL commands.

Threat Modeling

• SQL injection attacks allow attackers to spoof identity, tamper with existing data, cause repudiation issues such as voiding transactions or changing balances, allow the complete disclosure of all data on the system, destroy the data or make it otherwise unavailable, and become administrators of the database server.
• SQL Injection is very common with PHP and ASP applications due to the prevalence of older functional interfaces. Due to the nature of programmatic interfaces available, J2EE and ASP.NET applications are less likely to have easily exploited SQL injections.
• The severity of SQL Injection attacks is limited by the attacker’s skill and imagination, and to a lesser extent, defense in depth countermeasures, such as low privilege connections to the database server and so on. In general, consider SQL Injection a high impact severity.

Related Security Activities

How to Avoid SQL Injection Vulnerabilities

See the OWASP SQL Injection Prevention Cheat Sheet.
See the OWASP Query Parameterization Cheat Sheet.
See the OWASP Guide article on how to Avoid SQL Injection Vulnerabilities.

How to Review Code for SQL Injection Vulnerabilities

See the OWASP Code Review Guide article on how to Review Code for SQL Injection Vulnerabilities.

How to Test for SQL Injection Vulnerabilities

See the OWASP Testing Guide article on how to Test for SQL Injection Vulnerabilities.

How to Bypass Web Application Firewalls with SQLi

See the OWASP Article on using SQL Injection to bypass a WAF

Description

SQL injection errors occur when:

1. Data enters a program from an untrusted source.
2. The data used to dynamically construct a SQL query

The main consequences are:

• Confidentiality: Since SQL databases generally hold sensitive data, loss of confidentiality is a frequent problem with SQL Injection vulnerabilities.

• Authentication: If poor SQL commands are used to check user names and passwords, it may be possible to connect to a system as another user with no previous knowledge of the password.

• Authorization: If authorization information is held in a SQL database, it may be possible to change this information through the successful exploitation of a SQL Injection vulnerability.

• Integrity: Just as it may be possible to read sensitive information, it is also possible to make changes or even delete this information with a SQL Injection attack.

Risk Factors

The platform affected can be:

• Language: SQL
• Platform: Any (requires interaction with a SQL database)

SQL Injection has become a common issue with database-driven web sites. The flaw is easily detected, and easily exploited, and as such, any site or software package with even a minimal user base is likely to be subject to an attempted attack of this kind.

Essentially, the attack is accomplished by placing a meta character into data input to then place SQL commands in the control plane, which did not exist there before. This flaw depends on the fact that SQL makes no real distinction between the control and data planes.

Examples

Example 1

In SQL:

select id, firstname, lastname from authors

If one provided:

Firstname: evil'ex
Lastname: Newman

the query string becomes:

select id, firstname, lastname from authors where forename = 'evil'ex' and surname ='newman'

which the database attempts to run as:

Incorrect syntax near il' as the database tried to execute evil. 

A safe version of the above SQL statement could be coded in Java as:

String firstname = req.getParameter("firstname");
String lastname = req.getParameter("lastname");
// FIXME: do your own validation to detect attacks
String query = "SELECT id, firstname, lastname FROM authors WHERE forename = ? and surname = ?";
PreparedStatement pstmt = connection.prepareStatement( query );
pstmt.setString( 1, firstname );
pstmt.setString( 2, lastname );
try
{
 ResultSet results = pstmt.execute( );
}

Example 2

The following C# code dynamically constructs and executes a SQL query that searches for items matching a specified name. The query restricts the items displayed to those where owner matches the user name of the currently-authenticated user.

 ...
 string userName = ctx.getAuthenticatedUserName();
 string query = "SELECT * FROM items WHERE owner = "'" 
     + userName + "' AND itemname = '"  
     + ItemName.Text + "'";
 sda = new SqlDataAdapter(query, conn);
 DataTable dt = new DataTable();
 sda.Fill(dt);
 ...

The query that this code intends to execute follows:

 SELECT * FROM items
 WHERE owner = 
 AND itemname = ;

However, because the query is constructed dynamically by concatenating a constant base query string and a user input string, the query only behaves correctly if itemName does not contain a single-quote character. If an attacker with the user name wiley enters the string "name' OR 'a'='a" for itemName, then the query becomes the following:

 SELECT * FROM items
 WHERE owner = 'wiley'
 AND itemname = 'name' OR 'a'='a';

The addition of the OR 'a'='a' condition causes the where clause to always evaluate to true, so the query becomes logically equivalent to the much simpler query:

 SELECT * FROM items;

This simplification of the query allows the attacker to bypass the requirement that the query only return items owned by the authenticated user; the query now returns all entries stored in the items table, regardless of their specified owner.

Example 3

This example examines the effects of a different malicious value passed to the query constructed and executed in Example 1. If an attacker with the user name hacker enters the string "name'); DELETE FROM items; --" for itemName, then the query becomes the following two queries:

 SELECT * FROM items 
 WHERE owner = 'hacker'
 AND itemname = 'name';

 DELETE FROM items;

 --'

Many database servers, including Microsoft® SQL Server 2000, allow multiple SQL statements separated by semicolons to be executed at once. While this attack string results in an error in Oracle and other database servers that do not allow the batch-execution of statements separated by semicolons, in databases that do allow batch execution, this type of attack allows the attacker to execute arbitrary commands against the database.

Notice the trailing pair of hyphens (--), which specifies to most database servers that the remainder of the statement is to be treated as a comment and not executed. In this case the comment character serves to remove the trailing single-quote left over from the modified query. In a database where comments are not allowed to be used in this way, the general attack could still be made effective using a trick similar to the one shown in Example 1. If an attacker enters the string "name'); DELETE FROM items; SELECT * FROM items WHERE 'a'='a", the following three valid statements will be created:

 SELECT * FROM items 
 WHERE owner = 'hacker'
 AND itemname = 'name';

 DELETE FROM items;

 SELECT * FROM items WHERE 'a'='a';

One traditional approach to preventing SQL injection attacks is to handle them as an input validation problem and either accept only characters from a whitelist of safe values or identify and escape a blacklist of potentially malicious values. Whitelisting can be a very effective means of enforcing strict input validation rules, but parameterized SQL statements require less maintenance and can offer more guarantees with respect to security. As is almost always the case, blacklisting is riddled with loopholes that make it ineffective at preventing SQL injection attacks. For example, attackers can:

• Target fields that are not quoted
• Find ways to bypass the need for certain escaped meta-characters
• Use stored procedures to hide the injected meta-characters

Manually escaping characters in input to SQL queries can help, but it will not make your application secure from SQL injection attacks.

Another solution commonly proposed for dealing with SQL injection attacks is to use stored procedures. Although stored procedures prevent some types of SQL injection attacks, they fail to protect against many others. For example, the following PL/SQL procedure is vulnerable to the same SQL injection attack shown in the first example.

 procedure get_item (
  itm_cv IN OUT ItmCurTyp,
  usr in varchar2,
  itm in varchar2)
 is
  open itm_cv for ' SELECT * FROM items WHERE ' ||
    'owner = '''|| usr || 
    ' AND itemname = ''' || itm || '''';
 end get_item;

Stored procedures typically help prevent SQL injection attacks by limiting the types of statements that can be passed to their parameters. However, there are many ways around the limitations and many interesting statements that can still be passed to stored procedures. Again, stored procedures can prevent some exploits, but they will not make your application secure against SQL injection attacks.

Related Threat Agents

• Category:Command Execution
• Injection problem

Related Attacks

• Injection Risk (OWASP Top Ten 2013)
• SQL Injection Bypassing WAF
• Blind SQL Injection
• Code Injection
• Double Encoding
• Interpreter_Injection#ORM_Injection

Related Vulnerabilities

• Category:Input Validation Vulnerability

Related Controls

• Query Parameterization
• Input Validation

References

• SQL Injection Knowledge Base - A reference guide for MySQL, MSSQL and Oracle SQL Injection attacks.
• GreenSQL Open Source SQL Injection Filter - An Open Source database firewall used to protect databases from SQL injection attacks.
• An Introduction to SQL Injection Attacks for Oracle Developers - This also includes recommended defenses.
• OWASP SQLiX Project - An SQL Injection Scanner.
• Pangolin - Closed source SQL Injection Scanner.

Ethical Hacking - Wireless Hacking

A wireless network is a set of two or more devices connected with each other via radio waves within a limited space range. The devices in a wireless network have the freedom to be in motion, but be in connection with the network and share data with other devices in the network. One of the most crucial point that they are so spread is that their installation cost is very cheap and fast than the wire networks.

Wireless networks are widely used and it is quite easy to set them up. They use IEEE 802.11 standards. A wireless router is the most important device in a wireless network that connects the users with the Internet.

In a wireless network, we have Access Points which are extensions of wireless ranges that behave as logical switches.

Although wireless networks offer great flexibility, they have their security problems. A hacker can sniff the network packets without having to be in the same building where the network is located. As wireless networks communicate through radio waves, a hacker can easily sniff the network from a nearby location.

Most attackers use network sniffing to find the SSID and hack a wireless network. When our wireless cards are converted in sniffing modes, they are called monitor mode.

Kismet

Kismet is a powerful tool for wireless sniffing that is found in Kali distribution. It can also be downloaded from its official webpage − https://www.kismetwireless.net/index.shtml

Let’s see how it works. First of all, open a terminal and type kismet. Start the Kismet Server and click Yes, as shown in the following screenshot.

As shown here, click the Start button.

Now, Kismet will start to capture data. The following screenshot shows how it would appear −

NetStumbler

NetStumbler is another tool for wireless hacking that is primarily meant for Windows systems. It can be downloaded from http://www.stumbler.net/

It is quite easy to use NetStumbler on your system. You just have to click the Scanning button and wait for the result, as shown in the following screenshot.

It should display a screenshot as follows −

It is important to note that your card should support monitoring mode, otherwise you will fail to monitor.

Wired Equivalent Privacy

Wired Equivalent Privacy (WEP) is a security protocol that was invented to secure wireless networks and keep them private. It utilizes encryption at the data link layer which forbids unauthorized access to the network.

The key is used to encrypt the packets before transmission begins. An integrity check mechanism checks that the packets are not altered after transmission.

Note that WEP is not entirely immune to security problems. It suffers from the following issues −

• CRC32 is not sufficient to ensure complete cryptographic integrity of a packet.
• It is vulnerable to dictionary attacks.
• WEP is vulnerable to Denial of Services attacks too.

WEPcrack

WEPcrack is a popular tool to crack WEP passwords. It can be downloaded from − https://sourceforge.net/projects/wepcrack/

Aircrack-ng

Aircrak-ng is another popular tool for cracking WEP passwords. It can be found in the Kali distribution of Linux.

The following screenshot shows how we have sniffed a wireless network and collected packets and created a file RHAWEP-01.cap. Then we run it with aircrack-ng to decrypt the cypher.

Wireless DoS Attacks

In a wireless environment, an attacker can attack a network from a distance and therefore, it is sometimes difficult to collect evidences against the attacker.

The first type of DoS is Physical Attack. This type of attack is very basic and it is in the base of radio interferences which can be created even from cordless phones that operate in 2.4 GHz range.

Another type is Network DoS Attack. As the Wireless Access Point creates a shared medium, it offers the possibility to flood the traffic of this medium toward the AP which will make its processing more slow toward the clients that attempt to connect. Such attacks can be created just by a ping flood DoS attack.

Pyloris is a popular DoS tool that you can download from − https://sourceforge.net/projects/pyloris/

Low Orbit Ion Cannon (LOIC) is another popular tool for DoS attacks.

Quick Tips

To secure a wireless network, you should keep the following points in mind −

• Change the SSID and the network password regularly.
• Change the default password of access points.
• Don’t use WEP encryption.
• Turn off guest networking.
• Update the firmware of your wireless device.