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How the CVE Works:
CVE-2025-30377 is a use-after-free vulnerability in Microsoft Office that occurs when the software fails to clear a pointer after freeing memory. An attacker can craft a malicious document that triggers improper memory handling, leading to arbitrary code execution. When the victim opens the file, the exploit manipulates freed memory chunks to execute attacker-controlled payloads with the victim’s privileges. The flaw resides in object lifecycle management, where a dangling pointer remains accessible post-deallocation. Attackers leverage this to corrupt memory structures and hijack execution flow.
DailyCVE Form:
Platform: Microsoft Office
Version: 2019/2021/365
Vulnerability: Use-After-Free
Severity: Critical
Date: 05/19/2025
What Undercode Say:
Exploitation:
1. Craft malicious Office doc with embedded payload.
2. Trigger UAF via malformed object handling.
3. Overwrite freed memory with shellcode.
4. Gain code execution upon document open.
Detection:
strings malicious.doc | grep "ActiveX" procmon.exe /filter "ProcessName=winword.exe"
Mitigation:
1. Apply Microsoft patch KB4034567.
2. Disable macros via GPO:
Set-ItemProperty -Path "HKCU:\Software\Microsoft\Office\\Security" -Name "VBAWarnings" -Value 2
3. Use EMET to block exploitation:
EMET_Conf --enable_office_protections
Exploit PoC (Conceptual):
import olefile
ole = olefile.OleFileIO("exploit.doc")
ole.write_stream("\x00\x41" 1024, "\x90" 500 + shellcode)
Memory Analysis:
!heap -p -a <dangling_ptr_addr> !exploitable -v winword.exe
YARA Rule:
rule CVE_2025_30377 {
strings: $obj_header = {4F 4C 45 00}
condition: $obj_header at 0
}
References:
- MSRC Bulletin MS25-30377
- CWE-416: Use-After-Free
- Mitre ATT&CK T1204.002
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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