CVE-2018-0172 — AI Deep Analysis Summary

Q: What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: A flaw in Cisco IOS/IOS XE's DHCP Option 82 encapsulation. 🔥 **Consequences**: Remote attackers send crafted DHCPv4 packets → **Device Reload** (Denial of Service). No data theft, just downtime.

Q: Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: **CWE-20** (Improper Input Validation). ❌ **Flaw**: The software fails to perform **complete input validation** on Option 82 information. Malformed packets crash the system.

Q: Who is affected? (Versions/Components)

🏢 **Affected**: **Cisco IOS Software** & **IOS XE Software**. 📦 **Component**: DHCP Option 82 encapsulation feature. 🌍 **Vendor**: Cisco (USA).

Q: Is exploitation threshold high? (Auth/Config)

⚡ **Threshold**: **Low**. 🌐 **Auth**: **Remote** (No authentication required). ⚙️ **Config**: Exploits the DHCP Option 82 feature. If enabled/active, it's vulnerable.

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

📢 **Public Exp?**: **Yes**. 🔍 **Evidence**: References include Tenable TRA-2018-06 and SecurityTracker ID 1040591. 🌍 **Status**: Known exploitation vectors exist (ICSA advisories confirm risk).

Q: Is it fixed officially? (Patch/Mitigation)

🩹 **Official Fix**: **Yes**. 📅 **Published**: 2018-03-28. 📄 **Source**: Cisco Security Advisory (cisco-sa-20180328-dhcpr1). ✅ **Action**: Update to patched IOS/IOS XE versions.

Q: What if no patch? (Workaround)

🚧 **No Patch? Workaround**: 1. **Disable** DHCP Option 82 if not strictly needed. 2. Apply **Access Control Lists (ACLs)** to filter malicious DHCPv4 packets. 3. Monitor logs for **unexpected reloads**.

Updated May 06, 2026

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Q1What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: A flaw in Cisco IOS/IOS XE's DHCP Option 82 encapsulation. <br>🔥 **Consequences**: Remote attackers send crafted DHCPv4 packets → **Device Reload** (Denial of Service). No data theft, just downtime.

Q2Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: **CWE-20** (Improper Input Validation). <br>❌ **Flaw**: The software fails to perform **complete input validation** on Option 82 information. Malformed packets crash the system.

Q3Who is affected? (Versions/Components)

🏢 **Affected**: **Cisco IOS Software** & **IOS XE Software**. <br>📦 **Component**: DHCP Option 82 encapsulation feature. <br>🌍 **Vendor**: Cisco (USA).

Q4What can hackers do? (Privileges/Data)

💀 **Attacker Action**: Send **special crafted DHCPv4 packets**. <br>🔓 **Privileges**: **Remote** exploitation. <br>📉 **Impact**: **Denial of Service** (DoS). The device reboots unexpectedly.…

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Q5Is exploitation threshold high? (Auth/Config)

⚡ **Threshold**: **Low**. <br>🌐 **Auth**: **Remote** (No authentication required). <br>⚙️ **Config**: Exploits the DHCP Option 82 feature. If enabled/active, it's vulnerable.

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

📢 **Public Exp?**: **Yes**. <br>🔍 **Evidence**: References include Tenable TRA-2018-06 and SecurityTracker ID 1040591. <br>🌍 **Status**: Known exploitation vectors exist (ICSA advisories confirm risk).

Q7How to self-check? (Features/Scanning)

🔍 **Self-Check**: <br>1. Scan for **Cisco IOS/IOS XE** devices. <br>2. Check if **DHCP Option 82** is enabled. <br>3. Monitor for **DHCPv4 packet anomalies** or unexpected reboots. <br>4.…

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Q8Is it fixed officially? (Patch/Mitigation)

🩹 **Official Fix**: **Yes**. <br>📅 **Published**: 2018-03-28. <br>📄 **Source**: Cisco Security Advisory (cisco-sa-20180328-dhcpr1). <br>✅ **Action**: Update to patched IOS/IOS XE versions.

Q9What if no patch? (Workaround)

🚧 **No Patch? Workaround**: <br>1. **Disable** DHCP Option 82 if not strictly needed. <br>2. Apply **Access Control Lists (ACLs)** to filter malicious DHCPv4 packets. <br>3. Monitor logs for **unexpected reloads**.

Q10Is it urgent? (Priority Suggestion)

🔥 **Urgency**: **High**. <br>⚠️ **Reason**: Remote, unauthenticated DoS. <br>🏭 **Impact**: Critical for network infrastructure. <br>🚀 **Priority**: Patch immediately to prevent service disruption.…

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Vulnerability detail Full AI analysis (login) n/a CWE-20