Heap Overflow Havoc: Unpacking CVE-2025-47987 in Windows CredSSP

Introduction

A heap-based buffer overflow in Windows Credential Security Support Provider Protocol (CredSSP) has emerged as a critical security concern, identified as CVE-2025-47987. With a CVSS score of 7.8, this vulnerability enables authenticated attackers to escalate privileges locally, potentially gaining SYSTEM-level control. As CredSSP is integral to Windows Remote Desktop Services and authentication workflows, the implications for enterprise security are profound.

Technical Information

Vulnerability Mechanics

The flaw originates from improper bounds checking during the handling of authentication tokens within CredSSP. Specifically, when processing oversized authentication requests, CredSSP fails to validate input sizes, resulting in a heap-based buffer overflow. This overflow corrupts heap metadata, allowing attackers to manipulate memory allocation structures and execute arbitrary code.

CredSSP Architecture Context

CredSSP facilitates delegated authentication for protocols like Remote Desktop Protocol (RDP). The vulnerability specifically impacts the credssp.dll component, responsible for encrypting and transmitting authentication tokens. Insufficient validation during token encryption enables buffer overflow conditions.

Attack Vectors and Exploitation Methods

Attackers must possess valid local credentials and execution capabilities. Exploitation occurs via malicious applications or scripts that craft oversized authentication tokens, triggering heap overflow and enabling arbitrary memory overwrites. Successful exploitation results in SYSTEM-level privilege escalation.

// Simplified exploitation pseudocode
void exploit() {
    HANDLE hCredSSP = LoadLibrary("credssp.dll");
    crafted_token = create_oversized_token(1024); // Normal token: 256 bytes
    result = CredSSP_EncryptToken(hCredSSP, crafted_token); // Triggers overflow
    execute_shellcode(); // Post-escalation payload
}

Patch Information

Microsoft's July 2025 Patch Tuesday addressed 130 vulnerabilities, including CVE-2025-47987. Users should apply update KB5034951 immediately to mitigate this vulnerability. Regular updates ensure protection against known security risks.

Detection Methods

Advanced detection methods leveraging AI models like Gemini 1.5 Flash significantly enhance malware analysis capabilities. Gemini 1.5 Flash rapidly analyzes executables and DLLs, effectively identifying malicious activities and false positives. Integration with threat intelligence platforms further improves detection accuracy and response capabilities.

References

Security teams are encouraged to prioritize patching and leverage advanced detection methods to safeguard against exploitation of CVE-2025-47987.

Source: This report was created using AI

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