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T1564.007: VBA Stomping

View on MITRE ATT&CK The MITRE Corporation · Published 17/09/2020 14:51 · Modified 27/03/2026 01:11

Essential information

MITRE technique ID
T1564.007
Confidence
100/100
Revoked
No
Published
17/09/2020 14:51
Modified
27/03/2026 01:11
Author / Source
The MITRE Corporation

Aliases

T1564.007

Platforms

windows macos linux

Description

Adversaries may hide malicious Visual Basic for Applications (VBA) payloads embedded within MS Office documents by replacing the VBA source code with benign data.(Citation: FireEye VBA stomp Feb 2020) MS Office documents with embedded VBA content store source code inside of module streams. Each module stream has a `PerformanceCache` that stores a separate compiled version of the VBA source code known as p-code. The p-code is executed when the MS Office version specified in the `_VBA_PROJECT` stream (which contains the version-dependent description of the VBA project) matches the version of the host MS Office application.(Citation: Evil Clippy May 2019)(Citation: Microsoft _VBA_PROJECT Stream) An adversary may hide malicious VBA code by overwriting the VBA source code location with zero’s, benign code, or random bytes while leaving the previously compiled malicious p-code. Tools that scan for malicious VBA source code may be bypassed as the unwanted code is hidden in the compiled p-code. If the VBA source code is removed, some tools might even think that there are no macros present. If there is a version match between the `_VBA_PROJECT` stream and host MS Office application, the p-code will be executed, otherwise the benign VBA source code will be decompressed and recompiled to p-code, thus removing malicious p-code and potentially bypassing dynamic analysis.(Citation: Walmart Roberts Oct 2018)(Citation: FireEye VBA stomp Feb 2020)(Citation: pcodedmp Bontchev)

Kill chain phases

Kill chainPhase
mitre-attack defense-evasion

Marking (TLP)

TLP:CLEAR Copyright 2015-2025, The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation.

External references