CVE-2024-4009 — AI Deep Analysis Summary

Q: Who is affected? (Versions/Components)

🏢 **Affected Vendor**: ABB & Busch-Jaeger. 📦 **Specific Product**: **2.4! Display 55** (Model: SD/U12.55.11-825). 🏠 **Context**: Smart home and building automation systems.

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

📉 **Threshold**: **LOW**. 🔑 **Auth**: None required (PR:N). 📍 **Access**: Local (AV:L). 🖱️ **UI**: None needed (UI:N). ⚡ **Complexity**: Low (AC:L). Easy to exploit if on the local network.

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

🚫 **Public Exploit**: **No**. 📜 **Pocs**: Empty list in data. 🌐 **Wild Exploit**: Unlikely currently. 📝 **Note**: Reference link points to a security advisory, not a PoC code.

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

🩹 **Official Fix**: **Yes**. 📄 **Reference**: ABB Security Advisory (9AKK108464A0803). ⬇️ **Action**: Download the document from ABB's official library to find the patch or mitigation steps.

Q: Is it urgent? (Priority Suggestion)

⚡ **Urgency**: **HIGH**. 📊 **CVSS**: **7.5** (High). 🔥 **Reason**: No auth needed, high impact on integrity/availability. 🏃 **Action**: Patch immediately upon reviewing the ABB advisory. Do not ignore!

Updated May 08, 2026 CVSS 9.2 · Critical

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Q1What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: ABB KNX systems suffer from **FDSK leakage** and **Replay Attacks**. <br>💥 **Consequences**: Critical integrity loss, high availability impact, and sensitive data exposure.…

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Q2Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: The flaw lies in the cryptographic handling of **FDSK (Frame Data Security Key)**.…

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Q3Who is affected? (Versions/Components)

🏢 **Affected Vendor**: ABB & Busch-Jaeger. <br>📦 **Specific Product**: **2.4! Display 55** (Model: SD/U12.55.11-825). <br>🏠 **Context**: Smart home and building automation systems.

Q4What can hackers do? (Privileges/Data)

🕵️ **Attacker Actions**: <br>1. **Read**: Access low confidentiality data (C:L). <br>2. **Modify**: High integrity impact (I:H) – change system settings. <br>3.…

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Q5Is exploitation threshold high? (Auth/Config)

📉 **Threshold**: **LOW**. <br>🔑 **Auth**: None required (PR:N). <br>📍 **Access**: Local (AV:L). <br>🖱️ **UI**: None needed (UI:N). <br>⚡ **Complexity**: Low (AC:L). Easy to exploit if on the local network.

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

🚫 **Public Exploit**: **No**. <br>📜 **Pocs**: Empty list in data. <br>🌐 **Wild Exploit**: Unlikely currently. <br>📝 **Note**: Reference link points to a security advisory, not a PoC code.

Q7How to self-check? (Features/Scanning)

🔍 **Self-Check**: <br>1. Identify if you use **ABB KNX 2.4! Display 55**. <br>2. Check for **FDSK** configuration anomalies. <br>3. Monitor for **replay patterns** in KNX bus traffic. <br>4.…

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Q8Is it fixed officially? (Patch/Mitigation)

🩹 **Official Fix**: **Yes**. <br>📄 **Reference**: ABB Security Advisory (9AKK108464A0803). <br>⬇️ **Action**: Download the document from ABB's official library to find the patch or mitigation steps.

Q9What if no patch? (Workaround)

🛑 **No Patch Workaround**: <br>1. **Isolate**: Segment the KNX network from untrusted zones. <br>2. **Monitor**: Watch for repeated identical frames (Replay detection). <br>3.…

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Q10Is it urgent? (Priority Suggestion)

⚡ **Urgency**: **HIGH**. <br>📊 **CVSS**: **7.5** (High). <br>🔥 **Reason**: No auth needed, high impact on integrity/availability. <br>🏃 **Action**: Patch immediately upon reviewing the ABB advisory. Do not ignore!

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Vulnerability detail Full AI analysis (login) ABB, Busch-Jaeger