Hacking Vidhya

✎ The perils of the “real” client IP & X-Forwarded-For Header You've probably seen headers like these in common 403-bypass wordlists (e.g., my gist):

X-Forwarded-For: 127.0.0.1
X-Forwarded-Host: 127.0.0.1
X-Client-IP: 127.0.0.1

…and hundreds of similar variations (with 127.0.0.1, localhost, 192.168.1.1, internal IPs, etc.), but have you ever stopped to wonder why they sometimes actually work to bypass IP-based restrictions, rate limits, or 403/401 responses? The answer lies in how unreliable and inconsistent the handling of "real client IP" headers is when a web application sits behind a reverse proxy (whether that’s a CDN like Cloudflare, an AWS ALB, a simple Nginx instance, etc.). It’s quite challenging for developers, because there’s no universal, standardized way for proxies to convey the original visitor’s IP to the backend and even less consensus on how the backend should parse and trust that information. As a result, developers often rely on headers like X-Forwarded-For, X-Real-IP, or True-Client-IP to detect a visitor’s “real” IP address. But many frameworks use fragile logic especially the common pattern of trusting the left-most value in X-Forwarded-For. This is dangerous because the left-most entry is fully controlled by the client. Cloudflare, AWS ALB, and many other proxies append the real IP to the header instead of overwriting it. So an attacker can send:

X-Forwarded-For: 127.0.0.1

and it becomes:

127.0.0.1, <real attacker IP>

Many libraries (like go-chi/httprate in Go) will mistakenly trust that spoofed first value. The app then believes the user is localhost or a trusted internal IP and may skip rate limits, authentication checks, or internal-only protections entirely. This is not rare! dozens of frameworks and servers (Express, Jetty, IIS, Go libs, etc.) use inconsistent or insecure parsing strategies. The root problem: trusting client-controlled forwarding headers without restricting which proxies are allowed to set them. • I summarized the blog, but I highly recommend reading the full article here: Article #bugbounty #recon #HTTP #bypass

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How To Delete Files In Linux 100% 🗑 Every day we are deleting files for different reasons, so we are moving them to trash, but it's only away from our folder, not from our computer/laptop. So what we can do in Linux to remove it permanently? Maybe you heard about "Zero Filling", it's a method to overwrite something with zeros. It is often used by formatting (f. e. DBAN ), and also the process can not be undone. See also : How To Delete Files Completely A tool called shred can help us in this case. Our file is photo.jpg.

$ shred <options> <file>

-v = verbose output -f = change permissions to allow writing -z = add a final overwrite with zeros to hide shredding -u = deallocate and remove file after overwriting

$ shred -vfzu remmina_log_file.log                         
shred: remmina_log_file.log: pass 1/4 (random)...
shred: remmina_log_file.log: pass 2/4 (random)...
shred: remmina_log_file.log: pass 3/4 (random)...
shred: remmina_log_file.log: pass 4/4 (000000)...
shred: remmina_log_file.log: removing
shred: remmina_log_file.log: renamed to 00000000000000000000
shred: 00000000000000000000: renamed to 0000000000000000000
shred: 0000000000000000000: renamed to 000000000000000000
shred: 000000000000000000: renamed to 00000000000000000
shred: 00000000000000000: renamed to 0000000000000000
shred: 0000000000000000: renamed to 000000000000000
shred: 000000000000000: renamed to 00000000000000
shred: 00000000000000: renamed to 0000000000000
shred: 0000000000000: renamed to 000000000000
shred: 000000000000: renamed to 00000000000
shred: 00000000000: renamed to 0000000000
shred: 0000000000: renamed to 000000000
shred: 000000000: renamed to 00000000
shred: 00000000: renamed to 0000000
shred: 0000000: renamed to 000000
shred: 000000: renamed to 00000
shred: 00000: renamed to 0000
shred: 0000: renamed to 000
shred: 000: renamed to 00
shred: 00: renamed to 0
shred: remmina_log_file.log: removed

And you can try to recover it, but it's impossible.

seems like there are many professionals here , so why not to create a community of professionals and learners ? lemme know your toughts

❗️CrazyRDP has been seized❗️ Dutch Police Seize Thousands of Cybercrime Servers Dutch police have seized thousands of servers in The Hague and Zoetermeer that were used exclusively for cybercrime, including ransomware, botnets, phishing, and child sexual abuse material. The hosting company involved—linked to 80 investigations since 2022—marketed itself as a “bulletproof” provider offering anonymity to criminals. About 250 physical servers were taken on Wednesday, shutting down thousands of virtual machines. Police say the operation immediately disrupts ongoing crimes and enables further investigation of the seized data. The action follows an international Europol-led effort, during which Dutch authorities also took down 83 servers and 20 domains tied to services like CrazyRDP. No arrests have been made. Report Here ➡News

CACHE POISONING QUICK WIN: Most apps validate X-Forwarded-Host as a single value. But try this: X-Forwarded-Host: http://legit.com, http://evil.com • CDN: Reads first → Allows ✅ • App: Reads last → Injects

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CVE-2025-64495 * Open WebUI Stored DOM XSS Vuln POC

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If cybersecurity disappears tomorrow, what’s your plan B?

WAF bypass for XSS can be that simple, change the request method from GET to POST. The WAF was blocking the single quote we needed for an XSS payload, We managed to bypass by simply changing the request method from GET to POST which bypassed the WAF

New bug bounty resource 🚀 The Cache Poisoning Bible - Part 1: Advanced Fundamentals Everything I wish I knew when I started: • Cache key architectures • CDN comparison guide • Advanced detection methods • Real-world patterns https://medium.com/@Aacle/the-cache-poisoning-bible-part-1-advanced-fundamentals-2c8e9d7be2e9