Summary phpMyFAQ does not enforce uniqueness of email addresses during user registration. This allows multiple distinct accounts to be created with the same email. Because email is often used as an identifier for password resets, notifications, and administrative actions, this flaw can cause account ambiguity and, in certain configurations, may lead to privilege escalation or account takeover.

Details An account management logic flaw in phpMyFAQ allows attackers to register multiple accounts under the same email address. If email is used for password reset or administrative flows, this may result in account takeover, loss of accountability, and abuse of business logic. PoC

1.Register a user with email test@example.com 2.Register another user with the same email. 3.Both accounts appear in /admin/?action=user&useraction=listallusers. <img width="1150" height="628" alt="image" src="https://github.com/user-attachments/assets/8c19f01a-e897-4ca7-b3f8-fcf83e6ff952" />

Impact

-Data integrity loss: Multiple accounts mapped to one email break auditability. -Password reset ambiguity: If reset flow relies on email only, attackers can target or take over accounts. -Privilege escalation: If one account with the same email has admin privileges, an attacker controlling the email may escalate. -Spam / DoS: Attackers can mass-register accounts with a single email to pollute the system.

This is a business logic / authentication vulnerability. Impacted users are anyone relying on phpMyFAQ’s account system where email is assumed to be unique.

Unrestricted Upload of File with Dangerous Type in GitHub repository thorsten/phpmyfaq prior to 3.1.18.

phpMyFAQ before 2.9.8 does not properly mitigate brute-force attacks that try many passwords in attempted logins quickly.

Improper Neutralization of Formula Elements in a CSV File in GitHub repository thorsten/phpmyfaq prior to 3.1.16.

Weak Password Requirements in GitHub repository thorsten/phpmyfaq prior to 3.1.8.

Cross-site Scripting (XSS) - Reflected in GitHub repository thorsten/phpmyfaq prior to 3.1.9.

Cross-site Scripting (XSS) - Stored in GitHub repository thorsten/phpmyfaq prior to 3.1.10.

Improper Authentication in GitHub repository thorsten/phpmyfaq prior to 3.1.10.

Weak Password Requirements in GitHub repository thorsten/phpmyfaq prior to 3.1.10.

Code Injection in GitHub repository thorsten/phpmyfaq prior to 3.1.11.

Command Injection in GitHub repository thorsten/phpmyfaq prior to 3.1.11.

Authentication Bypass by Capture-replay in GitHub repository thorsten/phpmyfaq prior to 3.1.12.

Weak Password Requirements in GitHub repository thorsten/phpmyfaq prior to 3.1.12.

Improper Access Control in GitHub repository thorsten/phpmyfaq prior to 3.1.13.

Insufficient Session Expiration in GitHub repository thorsten/phpmyfaq prior to 3.2.2.

phpMyFAQ before v4.1.6 contains a remote code execution vulnerability in the configuration API that allows authenticated administrators with CONFIGURATIONEDIT and ATTACHMENTADD privileges to write arbitrary PHP files by manipulating the upgrade.lastDownloadedPackage setting. Attackers can upload a malicious ZIP file as an attachment, point the updater configuration to its stored path, and extract it into the application root to achieve code execution as the web server user.

phpMyFAQ before 4.1.2 contains an unauthenticated SQL injection vulnerability in BuiltinCaptcha::garbageCollector() and BuiltinCaptcha::saveCaptcha() methods that interpolate unsanitized User-Agent headers into DELETE and INSERT queries. Unauthenticated attackers can exploit the public GET /api/captcha endpoint by crafting malicious User-Agent headers to perform time-based blind SQL injection, extracting sensitive data including user credentials, admin tokens, and SMTP credentials from the database.

phpMyFAQ before 4.1.2 contains an improper restriction of excessive authentication attempts vulnerability in the /admin/check endpoint, which accepts arbitrary user-id parameters without session binding or rate limiting. Unauthenticated attackers can brute-force any user's six-digit TOTP code by submitting POST requests with sequential token values, bypassing two-factor authentication to gain full administrative access.

phpMyFAQ before 4.1.7 contains a brute-force vulnerability in the two-factor authentication step where the failure counter is session-scoped and reset on each successful password re-authentication. Attackers with a valid password can bypass the five-attempt limit by obtaining a fresh session cookie and repeatedly re-authenticating to reset the counter, enabling unbounded TOTP code guessing.

phpMyFAQ before 4.1.7 fails to persist the WebAuthn login challenge generated by prepareForLogin, because neither WebAuthn controller saves the mutated key objects back to the database. At login the anti-replay comparison is skipped by its own null guard, allowing an attacker who captures a successful WebAuthn assertion to replay it indefinitely and authenticate as the user without any interaction or hardware key.

Cross-site Scripting (XSS) - DOM in GitHub repository thorsten/phpmyfaq prior to 3.1.18.

Cross-site Scripting (XSS) - Stored in GitHub repository thorsten/phpmyfaq prior to 3.1.10.

Cross-site Scripting (XSS) - DOM in GitHub repository thorsten/phpmyfaq prior to 3.1.18.

The admin backend in phpMyFAQ before 2.9.11 allows CSV injection in reports.

Failure to Sanitize Special Elements into a Different Plane (Special Element Injection) in GitHub repository thorsten/phpmyfaq prior to 3.1.12.

Summary A SQL injection vulnerability has been discovered in the the "Add News" functionality due to improper escaping of the email address. This allows any authenticated user with the rights to add/edit FAQ news to exploit this vulnerability to exfiltrate data, take over accounts and in some cases, even achieve RCE.

Details The vulnerable field lies in the authorEmail field which uses PHP's FILTERVALIDATEEMAIL filter. This filter is insufficient in protecting against SQL injection attacks and should still be properly escaped. However, in this version of phpMyFAQ (3.2.5), this field is not escaped properly can be used together with other fields to fully exploit the SQL injection vulnerability.

PoCs 4 PoCs are demonstrated here to illustrate the potential impacts.

PoC 1 - Postgres Time Based SQLi 1. Login as admin or any user with the rights to view and save news. 2. Navigate to "../phpmyfaq/admin/?action=news", click on "Add news", fill in some data, send and intercept the request. 3. Modify the intercepted "/admin/?action=save-news" request to look like the SS below: 3.1 - Set the "authorEmail" field in the body to "test'/@email.com". 3.2 - Set the "linkTitle" field in the body to "/,1,1,1,1,1,1,1);select+pgsleep(5)--". 3.3 - Set the rest of the fields as empty and send the request. 4. Notice the 5s delay in the response time, indicating that the sleep function was executed, verifying the existence of the SQLi vulnerability. !image

PoC 2 - SQLi to Read Data from PostgresDB 1. Steps 1 and 2 are the same as PoC 1. 2. Modify the intercepted "/admin/?action=save-news" request to look like the SS below and send the request: 2.1 - Set the "authorEmail" field in the body to "test'/@email.com". 2.2 - Set the "linkTitle" field in the body to "/,1,1,1,1,1,1,1);SELECT+rememberme+FROM+faquser+limit+1+offset+1%3b--". !image (1)

PoC 3 - SQLi to Read Files from PostgresDB 1. Steps 1 and 2 are the same as PoC 1. 2. Modify the intercepted "/admin/?action=save-news" request to look like the SS below and send the request: 2.1 - Set the "authorEmail" field in the body to "test'/@email.com". 2.2 - Set the "linkTitle" field in the body to "/,1,1,1,1,1,(select+pgreadfile(CONCAT(CHR(67),CHR(58),CHR(92),CHR(87),CHR(105),CHR(110),CHR(100),CHR(111),CHR(119),CHR(115),CHR(92),CHR(119),CHR(105),CHR(110),CHR(46),CHR(105),CHR(110),CHR(105)))),1)--". (the CONCAT() and CHR() functions are used to bypass the escaping of single quotes, these characters in its decoded form is "select pgreadfile('C:\Windows\win.ini')") !image (2)

PoC 4 - SQLi to Shell It is also possible to obtain a shell if superuser is enabled on the postgres DB. These are the high level steps of the exploit chain:

1. Create a table called "cmdexec" to store the payload. 2. Create a function in postgres to store the command to write a web shell to the "../htdocs" directory. (This step is required as CONCAT() function cannot be used to bypass the step where; "COPY cmdexec FROM PROGRAM '<command>' " is run as it requires single quotes.) 3. Trigger the function to write the PHP web shell at "http://<URL>/shell.php" that takes in commands via the "?cmd=" parameter. 4. Send the Python reverse shell command via a GET request to launch the reverse shell.

The video demo and the Python PoC script can be accessed from this link: https://drive.google.com/drive/folders/1BFL8GHIBxSUxu0TneYf66KjFA0A4RZga?usp=sharing

Impact The SQL injection vulnerability discovered in the "Add News" functionality of the application allows authenticated users with appropriate privileges to execute malicious SQL queries, potentially leading to data exfiltration, account takeover, and even remote code execution. Attackers can exploit the vulnerability to read sensitive data from the database, such as user credentials and system files, compromising the confidentiality and integrity of the system. Moreover, successful exploitation may enable attackers to gain unauthorized access to user accounts or execute arbitrary commands on the server, impacting both system administrators and end users.

Summary A SQL injection vulnerability has been discovered in the insertentry & saveentry when modifying records due to improper escaping of the email address. This allows any authenticated user with the rights to add/edit FAQ news to exploit this vulnerability to exfiltrate data, take over accounts and in some cases, even achieve RCE.

PoC 1 - SQL Injection at insertentry: 1. Browse to “/admin/?action=editentry”, edit record and save. Intercept the POST request to "/admin/?action=insertentry" and modify the email and notes parameters in the body to the payloads below: a. email=test'/@email.com b. notes=/,1,1,1,1,null,1);select+pgsleep(5)--

2. Send the request and notice the pgsleep(5) command is executed with a time delay of 5 seconds in the response. This verifies that the SQL injection vulnerability exists. !image

PoC 2 - SQL Injection at saveentry 1. Browse to “/admin/?action=editentry”, edit record and save. Intercept the POST request to "/admin/?action=saveentry" and modify the email and notes parameters in the body to the payloads below: a. email=test'/@email.com b. /,notes=(select+pgsleep(5))-- 2. Send the request and notice the pgsleep(5) command is executed with a time delay of 5 seconds in the response. This verifies that the SQL injection vulnerability exists. !image

Impact The SQL injection vulnerability discovered allows authenticated users with appropriate privileges to execute malicious SQL queries, potentially leading to data exfiltration, account takeover, and even remote code execution. Attackers can exploit the vulnerability to read sensitive data from the database, such as user credentials and system files, compromising the confidentiality and integrity of the system. Moreover, successful exploitation may enable attackers to gain unauthorized access to user accounts or execute arbitrary commands on the server, impacting both system administrators and end users.

phpMyFAQ before 4.1.3 contains an authentication bypass vulnerability in the password reset endpoint that allows unauthenticated attackers to reset any user account password without token verification or email confirmation. Attackers can enumerate valid usernames, obtain plaintext passwords via email, and achieve complete account takeover including administrative access.

phpMyFAQ before 4.1.3 contains an unauthenticated password reset vulnerability in the user password update API endpoint that allows attackers to change account passwords without token validation. Attackers can enumerate valid username and email pairs and force immediate password changes by sending PUT requests to the /api/index.php/user/password/update endpoint, causing account disruption and invalidating legitimate user credentials.

phpMyFAQ versions 3.1.0 through 4.1.6 contain an authentication bypass vulnerability in AuthLdap::create(). When LDAP authentication is enabled, after a successful LDAP bind the code calls User::setStatus('active') unconditionally, which overwrites the accountstatus column of a pre-existing local account from 'blocked' to 'active'. As a result, a user whose local phpMyFAQ account has been administratively blocked can restore their account and log in by authenticating via LDAP. The state transition is not logged, so administrators cannot detect that the block was overridden. Fixed in 4.1.7.