Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c4bf1fbef7e234b5…

MALICIOUS

Office (OLE)

301.2 KB Created: 2019-02-18 14:23:00 Authoring application: Microsoft Office Word First seen: 2019-05-16
MD5: 81f74c1304681e662021be1ec3f99569 SHA-1: 12ee42933965ea8eeff05273cce77c275486b2db SHA-256: c4bf1fbef7e234b550a457906fc4e7497d19cb2856526b3c3becdad1732d08d4
70 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The presence of a legacy WordBasic auto-exec marker ('autoopen') strongly suggests the document is intended to automatically execute malicious code upon opening. The OLE slack anomaly indicates potential obfuscation or padding within the file structure. While no specific payload or C2 communication was directly observed, the auto-exec macro is a clear indicator of malicious intent, likely to download and execute a second-stage payload.

Heuristics 4

  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 308,480 bytes but its declared streams total only 149,805 bytes — 158,675 bytes (51%) live in unallocated sector slack. This is the canonical hiding place for pre-macro-era Office exploit payloads (XOR-encoded shellcode reached via a parser pointer-corruption bug in the document structure).
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 311 bytes
SHA-256: f818148234379588ca9ea5582cee798204557e55331cbf2d88c2b6bdbe92d0ab
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "K_2_08"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "j4_295"

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