Articles & Guides
Useful resources for web developers and system administrators
Found 68 · Security · Reset
Security
PHP2Shell (CVE-2026-109618, CVE-2026-109619) — PHP RCE: who is affected and how to check
PHP2Shell: critical PHP RCE (CVSS 9.2), exploited in the wild, in CISA KEV. Fixed in 8.2.35, 8.3.36, 8.4.27, 8.5.12. How to check and what to do.
Security
What Is Kali Linux Used For? Uses, Install, Legality
What Kali Linux is used for, whether it is legal, where to download official images, how to run it in VirtualBox or WSL, and the default kali/kali login.
Security
What Is a Trojan? How It Works and How to Remove One
What a Trojan is, how it differs from a virus and a worm, the main types, warning signs, and step-by-step removal on Windows 10/11 and Android — plus web shells.
Security
What Is Roskomnadzor (RKN)? Russia's Internet Regulator
What Roskomnadzor (RKN) is, which registries it keeps, how Russian site blocking works and what it means for foreign site owners: data, ads, reachability.
Security
What Is a Firewall? How It Works and How to Configure One
What a firewall is and how it works: stateless vs stateful vs WAF, Windows Defender Firewall rules, ufw, firewalld and nftables, Docker and cloud traps, port checks.
Security
Russia's Personal Data Operators Registry: Check and File
How Roskomnadzor's personal data operators registry works: who must notify under 152-FZ Article 22, how to search by INN, and how to file or update an entry.
Security
OSINT for Domains and Websites: What to Check and How
OSINT for websites explained: what WHOIS/RDAP, DNS, crt.sh certificate logs, IP and ASN data, reverse IP and the Wayback Machine reveal, with commands and tools.
Security
Check a File for Viruses Online: Scanners, Hashes, Reports
How to check a file for viruses online: VirusTotal, OpenTIP, MetaDefender, SHA-256 lookups without uploading, reading detections and scanning files over 1 GB.
Security
MTA-STS and TLS-RPT: The Control That Can Stop Mail
SPF and DMARC change how mail is classified; MTA-STS changes whether it is delivered. Roll it out with TLS-RPT first, and know what enforce mode really costs.
Security
Cloudflare Error 1015: Why Your Own Visitors Are Rate Limited
Error 1015 is a rule you configured, firing. Find which one matched, check what it counts by, and stop it catching customers, mobile users and your monitoring.