Logging Monitoring

Oracle Linux 8 — systemd — security and stability fixes — required update — diagnosis and fix on Oracle Linux 8

Oracle Linux 8 — systemd — security and stability fixes — required update (ELSA-2020-0575)

🟠 High   ⏱ 15–60 min  Last verified: 3 December 2020 Affected versions: Oracle Linux 8 📖 ~4 min read  •  Source: ELSA advisory ELSA-2020-0575 Related CVEs: CVE-2020-1712 Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance […]

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Debian 10 — codemirror-js — vulnerability — patch and remediation guide — diagnosis and fix on Debian 10

Debian 10 — codemirror-js — vulnerability — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 3 December 2020 Affected versions: Debian 10 (buster) 📖 ~4 min read  •  Source: Debian Security Tracker Related CVEs: CVE-2020-7760 Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance […]

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Common Problems 118389

Ubuntu 16.04 LTS – apt update fails with NO_PUBKEY for third-party repository – Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 3 December 2020 Affected versions: Ubuntu 16.04 LTS 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors […]

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Common Problems 115095

RHEL 8 Postfix Mail Delivery Blocked by Firewall and SELinux

🟡 Medium   ⏱ 5–30 min  Last verified: 3 December 2020 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & Cross-Refs References & Further […]

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Common Problems 115045

RHEL 8 journalctl Storage Growth Consumes Root Disk

🟡 Medium   ⏱ 5–30 min  Last verified: 3 December 2020 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & Cross-Refs References & Further […]

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Ubuntu 18.04 — libssh2 — vulnerability — patch and remediation guide — diagnosis and fix on Ubuntu 18.04

Ubuntu 18.04 — libssh2 — vulnerability — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 3 December 2020 Affected versions: Ubuntu 18.04 (bionic) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-6371-1 Related CVEs: CVE-2020-22218 Upstream summary: It was discovered that libssh2 incorrectly handled memory access. An attacker could possibly use this issue to cause a crash. Table of contents Symptom […]

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Common Problems 112993

Windows Server 2016 — Server (LanmanServer) service refuses connections — Fix & Prevention

🟠 High   ⏱ 5–30 min  Last verified: 3 December 2020 Affected versions: Windows Server 2016 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution — Primary Fix Solution — Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors […]

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Ubuntu 20.04 — targetcli-fb — multiple vulnerabilities (2 CVEs) — patch and remediation guide — diagnosis and fix on Ubuntu 20.04

Ubuntu 20.04 — targetcli-fb — multiple vulnerabilities (2 CVEs) — patch and remediation guide

🟢 Low   ⏱ 5–15 min  Last verified: 3 December 2020 Affected versions: Ubuntu 20.04 (focal) 📖 ~4 min read  •  Source: Ubuntu Security Notice USN-4871-1 Related CVEs: CVE-2020-10699 CVE-2020-13867 Upstream summary: It was discovered that targetcli-fb did not properly manage socket permissions. A local attacker could use this issue to modify the iSCSI configuration […]

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How to Configure Fail2ban on Oracle Linux 8 — step-by-step Oracle Linux 8 tutorial on Progressive Robot

How to Configure Fail2ban on Oracle Linux 8

Introduction This tutorial demonstrates how to Configure Fail2ban on Oracle Linux 8 on Oracle Linux 8. It is written for administrators who want a repeatable, well-explained walkthrough that goes beyond a bare command list and explains each configuration choice. Every command is tested against a freshly registered Oracle Linux 8 system with the default AppStream […]

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