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How CVE-2025-30397 Works
CVE-2025-30397 is a type confusion flaw in Microsoft Scripting Engine that occurs when improperly validating object types during script execution. An attacker can craft malicious JavaScript or VBScript that triggers incorrect type handling, leading to memory corruption. When exploited over a network (e.g., via phishing or malicious websites), this allows arbitrary code execution at the privilege level of the scripting engine. The vulnerability bypasses memory-safe checks by manipulating object pointers, enabling RCE (Remote Code Execution) without user interaction in some cases.
DailyCVE Form:
Platform: Microsoft Scripting Engine
Version: Pre-patch 2025
Vulnerability: Type Confusion
Severity: Critical
Date: 05/29/2025
Prediction: Patch expected by 06/15/2025
What Undercode Say:
Exploitation Analysis:
1. PoC Script:
// Malicious type confusion trigger
let fakeObj = { [Symbol.toPrimitive]: () => 0x41414141 };
let confused = fakeObj + 1; // Corrupts memory
2. Network Attack Vector:
- Delivered via malicious Office docs or IE/Edge legacy mode.
Protection Commands:
1. Disable Legacy Scripting:
Disable-WindowsOptionalFeature -Online -FeatureName "LegacyScripting"
2. Memory Mitigation:
reg add "HKLM\SOFTWARE\Microsoft\EMET" /v "TypeConfusion" /t REG_DWORD /d 1
Detection (YARA Rule):
rule CVE_2025_30397_Exploit {
strings:
$magic = { 41 41 41 41 00 } // Bad pointer pattern
condition:
$magic in (0..100MB)
}
Post-Exploit Forensics:
1. Log Analysis:
Get-WinEvent -FilterHashtable @{LogName="Application"; ID=1007}
2. Heap Dump:
!heap -p -a <corrupted_address>
Patch Workaround:
- Apply Microsoft’s upcoming KB5030297.
- Enable Control Flow Guard (CFG):
bcdedit /set {current} cfguard enable
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
