Question 1

What is this vulnerability? (Essence + Consequences)

Accepted Answer

🚨 **Essence**: OpenSSH has a logic error in `VerifyHostKeyDNS` handling.
💥 **Consequences**: Enables **Man-in-the-Middle (MitM)** attacks.…

Question 2

Root Cause? (CWE/Flaw)

Accepted Answer

🔍 **Root Cause**: **CWE-390** (Detection of Error Condition Without Action).
⚠️ **Flaw**: Improper error code processing when `VerifyHostKeyDNS` is enabled.…

Question 3

Who is affected? (Versions/Components)

Accepted Answer

📦 **Affected**: OpenSSH versions **6.8p1 to 9.9p1** (inclusive).
🔑 **Condition**: Vulnerable only if the client has `VerifyHostKeyDNS` option **enabled**. 📋

Question 4

What can hackers do? (Privileges/Data)

Accepted Answer

🕵️ **Hackers Can**: Perform **active MitM attacks**.
🎭 **Action**: Impersonate a legitimate server.
📊 **Impact**: **High** impact on Confidentiality (C:H) and Integrity (I:H).…

Question 5

Is exploitation threshold high? (Auth/Config)

Accepted Answer

📊 **Threshold**: **High** (AC:H).
🔐 **Requirements**:
1. User interaction required (UI:R).
2. No privileges needed (PR:N).
3. Network accessible (AV:N).…

Question 6

Is there a public Exp? (PoC/Wild Exploitation)

Accepted Answer

🔓 **Public Exp**: **Yes**.
📂 **PoC**: Available on GitHub (e.g., `rxerium/CVE-2025-26465`).
🌍 **Status**: Active MitM attack methods are documented and accessible. ⚠️

Question 7

How to self-check? (Features/Scanning)

Accepted Answer

🔎 **Self-Check**:
1. Check OpenSSH version (6.8p1-9.9p1).
2. Verify if `VerifyHostKeyDNS` is **enabled** in client config.
3. Use scanners matching SSH banners like `SSH-2.0-OpenSSH_7.0p1`. 📝

Question 8

Is it fixed officially? (Patch/Mitigation)

Accepted Answer

🛡️ **Official Fix**: **Yes**.
📅 **Date**: Published 2025-02-18.
📜 **Advisories**: Red Hat (RHSA-2025:3837, etc.) provide patches. Update OpenSSH to latest version. ✅

Question 9

What if no patch? (Workaround)

Accepted Answer

🚧 **No Patch?**: **Mitigation**.
⚙️ **Action**: Disable `VerifyHostKeyDNS` in SSH client config.
📜 **Tool**: Use manual patch scripts (e.g., `mitigacao-openssh.sh`) to apply config changes immediately. 🛠️

Question 10

Is it urgent? (Priority Suggestion)

Accepted Answer

⚡ **Urgency**: **High Priority**.
📈 **CVSS**: High (C:H, I:H).
🎯 **Reason**: Active MitM allows credential theft/session hijacking. Immediate mitigation (disable DNS verification) or patching is critical. 🚨

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CVE-2025-26465 — AI Deep Analysis Summary

Q1What is this vulnerability? (Essence + Consequences)

Q2Root Cause? (CWE/Flaw)

Q3Who is affected? (Versions/Components)

Q4What can hackers do? (Privileges/Data)

Q5Is exploitation threshold high? (Auth/Config)

Q6Is there a public Exp? (PoC/Wild Exploitation)

Q7How to self-check? (Features/Scanning)

Q8Is it fixed officially? (Patch/Mitigation)

Q9What if no patch? (Workaround)

Q10Is it urgent? (Priority Suggestion)

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