CVE-2021-23758 — AI Deep Analysis Summary

🚨 **Essence**: A critical deserialization flaw in **Ajax.NET Professional** (AjaxPro).…

🛡️ **Root Cause**: Unsafe Deserialization. The framework allows the deserialization of **arbitrary .NET classes** without proper validation.…

📦 **Affected**: **Ajax.NET Professional** (specifically **AjaxPro.2**). It is an early AJAX framework for **Microsoft ASP.NET**. Any application using this specific library version is at risk. 📉

🔓 **Privileges/Data**: **Full Control**. The CVSS score is **High (H)** for Confidentiality, Integrity, and Availability.…

📊 **Exploitation Threshold**: **Low/Medium**. **Auth**: No authentication required (PR:N). **Network**: Remote (AV:N). **Complexity**: High (AC:H) implies specific payload crafting is needed, but it’s still exploitable.…

🔥 **Public Exp?**: **YES**. A public PoC exists on GitHub (`numanturle/CVE-2021-23758-POC`). It demonstrates a POST request to `/ajaxpro/...` with a specific `X-Ajaxpro-Method` header.…

🔍 **Self-Check**: Scan for **AjaxPro** libraries in your ASP.NET projects. Look for endpoints containing `/ajaxpro/` or references to `AjaxPro.2.dll`. Use DAST tools that detect deserialization vulnerabilities.…

🩹 **Official Fix**: **YES**. The vendor (Michael Schwarz) released a fix. See commit `b0e63be5f0bb20dfce507cb8a1a9568f6e73de57` on GitHub. Update to the patched version immediately! 🛠️

🚧 **No Patch?**: **Mitigation**: Remove or disable the **AjaxPro** handler if not strictly needed. Implement **WAF rules** to block suspicious POST requests to `/ajaxpro/` endpoints.…

⚠️ **Urgency**: **HIGH**. CVSS is high, RCE is possible, and PoC is public. Patch **immediately**. This is not a theoretical risk; it’s an active threat vector for ASP.NET applications using this legacy framework. 🚨