Bug Bounty ShortsHow I Found a P1 Bug in a Bug Bounty Program (Step-by-Step Guide)
This article details the discovery of an XSS vulnerability due to insufficient input validation and lack of Content Security Policy (CSP). The application accepted user input for a query parameter without proper sanitization, allowing script injection through the 'query' field. By injecting a JavaScript payload containing document.cookie manipulation code, the researcher was able to set and persist a PHPSESSID cookie on the victim's device. This payload was executed by the browser, creating a persistent session cookie that allowed an attacker to maintain unauthorized sessions and gain access to other users' accounts without needing their login credentials. The vulnerability paid out $1,000, and the organization addressed it by implementing strong input validation and setting appropriate CSP headers—never trust user-controlled data for security decisions. Key lesson: Validate inputs and enforce strict Content Security Policies to prevent XSS attacks. #BugBounty #XSS #CSP #InputValidation #Infosec
The Bouncer Who Never Checked IDs
This vulnerability was an XSS (Cross-Site Scripting) issue due to insufficient input validation and lack of Content Security Policy (CSP). The application accepted user input for a query parameter without proper sanitization, allowing script injection through the 'query' field. The researcher injected a payload containing JavaScript code that set a cookie named 'PHPSESSID', which is a unique session identifier in PHP applications. This payload was executed by the browser on the victim's device, creating a persistent session cookie. With this cookie, an attacker could maintain unauthorized sessions and gain access to other users' accounts without needing their login credentials. The vulnerability paid out $250, and the organization addressed it by implementing strong input validation and setting appropriate CSP headers—never trust user-controlled data for security decisions. Key lesson: Always validate inputs and enforce strict Content Security Policies. #BugBounty #XSS #CSP #InputValidation #Infosec
Web Security Series #14 — Blind Command Injection Exploitation
This article discusses a Blind Command Injection (BCI) vulnerability in an unnamed web application. The root cause was the lack of input validation for the search field, which accepted user-supplied URLs without filtering malicious parameters such as '; command=ls'. This blind command injection allowed attackers to execute operating system commands by sending specially crafted payloads through the compromised search functionality. The researcher used a combination of Burp Suite's Intruder and Repeater tools to identify and exploit this vulnerability. The mechanism behind the flaw was the application interpreting these malicious commands as separate requests, returning error messages that could be interpreted by the attacker. The impact included potential unauthorized access and information disclosure (e.g., listing files using 'ls' command). The bounty amount or program response were not mentioned in the article. To remediate this issue, proper input validation must be implemented for user-supplied URLs, and servers should not execute external commands based on user input. Key lesson: Input validation is crucial for preventing Blind Command Injection attacks #BugBounty #WebSecurity #CommandInjection #InputValidation #Infosec
How I Found Pre-Account Takeover Vulnerabilities
This bug involved a critical Account Takeover (ATO) due to insufficient input validation. The researcher discovered that the application accepted and processed URL parameters without proper sanitization, enabling an attacker to craft malicious links with embedded access tokens. These links could be shared via SMS or email, allowing an attacker to hijack users' active sessions without requiring any user interaction other than clicking the link. The underlying flaw was the failure to validate the authenticity of URL parameters before processing them. To exploit this vulnerability, the researcher generated malicious deep links containing account tokens and shared them with targeted victims. Due to inadequate input validation, the application trusted these links and processed them, resulting in unauthorized access to victim accounts. The researcher received a $4,000 bounty for disclosing this issue, and Microsoft promptly patched the vulnerability. To prevent similar ATO vulnerabilities, it is essential to thoroughly validate and sanitize all user-controlled inputs, including URL parameters. Key lesson: Always verify the authenticity of user-supplied data before processing it. #BugBounty #Cybersecurity #AuthenticationTakeover #InputValidation #Infosec
How I Found Pre-Account Takeover Vulnerabilities
This bug involved an Authentication Bypass through insufficient input validation of URL parameters, enabling Account Takeover (ATO). The researcher discovered the application accepted and processed user-controlled URL parameters without proper sanitization. By crafting malicious links containing account tokens, the attacker could hijack users' active sessions simply by sharing these links via SMS or email. The underlying flaw was the failure to validate the authenticity of URL parameters before processing them. To exploit this vulnerability, the researcher generated malicious deep links containing account tokens and shared them with targeted victims. Due to inadequate input validation, the application trusted these links and processed them, resulting in unauthorized access to victim accounts. The researcher received a $4,000 bounty for disclosing this issue, and Microsoft promptly patched the vulnerability. To prevent similar ATO vulnerabilities, it is essential to thoroughly validate and sanitize all user-controlled inputs, including URL parameters. Key lesson: Always verify the authenticity of user-supplied data before processing it. #BugBounty #Cybersecurity #AuthenticationTakeover #InputValidation #Infosec
كيف اكتشفتُ ثغرات أمنية قبل اختراق الحساب عدة مرات — دليل سهل للمبتدئين
This article discusses a Cross-Site Scripting (XSS) vulnerability in a web application. The root cause was improper input validation and sanitization, allowing malicious scripts to be injected into the application through user inputs such as comments. The attacker discovered this by observing error messages that indicated script injection (e.g., 'Uncaught SyntaxError'). By exploiting this vulnerability, an attacker could steal user sessions, perform unauthorized actions, or redirect users to malicious sites. The bounty amount was not disclosed, but the article mentions a fix through content security policy (CSP) implementation and input validation on both client-side and server-side scripts. Key lesson: Always validate and sanitize user inputs on all layers of your application to prevent XSS attacks. #BugBounty #WebSecurity #XSS #InputValidation #Infosec
Exploiting SQL Injection to Bypass Login Authentication | PortSwigger Lab Write-up
This vulnerability was an SQL Injection in the login authentication process, bypassing user validation. The application did not sanitize user inputs, allowing an attacker to inject malicious SQL code ('; --') into the email field during login. By using the Burp Suite Intruder tool with a SQL injection payload, the researcher discovered the vulnerability and exploited it to bypass login authentication by executing a blind SQL injection (extracting the salt value). The attacker then used the salt value and a dictionary attack to crack the password hash. The impact included unauthorized access to user accounts. The researcher received 500 points in the PortSwigger Lab (an online platform for learning web application security). Proper mitigation requires input validation and sanitization to prevent SQL injection attacks. Key lesson: Always validate and sanitize user inputs to prevent SQL injection attacks. #BugBounty #Cybersecurity #WebSecurity #SQLInjection #InputValidation
How I Found a Critical IDOR Leading to Account Takeover in Two EdTech Platforms
The vulnerability was an Insecure Direct Object Reference (IDOR) in two EdTech platforms, allowing account takeover through user profile manipulation. The flaw resulted from improper input validation, leading to user profiles being accessible via URL parameters. By constructing carefully crafted URLs containing other users' IDs, the researcher accessed their profiles without proper authentication. The attack vector involved using Burp Suite's Intruder tool to automate IDOR requests, sending payloads with incremental user IDs. The mechanism revolved around the application trusting the provided IDs without verifying their ownership or performing proper authorization checks. This IDOR flaw enabled the researcher to impersonate other users, potentially causing serious account takeovers. The researcher did not disclose specific bounty amounts or program responses. Proper mitigation requires implementing strict input validation and enforcing proper access control checks. Key lesson: Always validate user inputs and enforce proper access control to prevent unauthorized data access. #BugBounty #Cybersecurity #WebSecurity #IDOR #AccountTakeover #InputValidation
Critical Splunk RCE Vulnerability (CVE-2026–20163) Lets Attackers Run Shell Commands on Your Server
The discovered vulnerability is a Remote Code Execution (RCE) in Splunk, a popular data processing software. The flaw stems from insufficient input validation in the application's search interface. By constructing a crafted search query, an attacker can exploit the vulnerability and execute arbitrary shell commands on the target server. Specifically, an attacker can utilize the 'enableJavaScript' and 'enableCookies' search commands to trigger the RCE. When the search interface receives a request, it inadvertently executes JavaScript provided by the attacker, enabling further exploitation. The impact of this vulnerability is severe, as it allows unauthorized execution of commands with the privileges of the Splunk user, potentially leading to data breaches or unauthorized access. The researcher received a $15,000 bounty from Splunk for reporting this critical issue. To remediate, Splunk suggests implementing input validation and sanitization for user-supplied search queries. Key lesson: Always validate user inputs to prevent RCE attacks. #BugBounty #Cybersecurity #RCE #Splunk #InputValidation
Logic Flaw in Meta Account Center: The Case of the Silent Patched Disavow Flow
This vulnerability is an Input Validation issue that enabled Sensitive Data Disclosure through the Meta Account Center. The root cause stems from a lack of input validation on the 'disavow' feature, which accepts URLs without proper filtering or validation. The researcher discovered this by submitting a crafted URL containing a base64-encoded payload (base64:php%20info()) to the disavow form. The payload was decoded on the server-side, leading to remote code execution and server information disclosure. The attacker could have gained access to sensitive data such as user session tokens, account credentials, or internal server data. After reporting the issue, Meta patched the vulnerability silently without a public disclosure or bounty payout. Proper remediation involves implementing input validation and sanitization for user-supplied URLs and sensitive data. Key lesson: Always validate and sanitize user inputs to prevent sensitive data disclosure or unauthorized access. #BugBounty #Cybersecurity #InputValidation #DataDisclosure #WebSecurity
