Malicious Office (OLE) / .BAK — malware analysis report

Static analysis result for SHA-256 e7fdb0778c6fde0d…

MALICIOUS

Office (OLE) / .BAK

252.0 KB Created: 2007-01-19 05:34:10 Authoring application: Microsoft Excel
MD5: 55e8311212ad2bce95f707a89fcbfc2c SHA-1: 83e401dfa4511bf9978bb036f6105333e8903a2f SHA-256: e7fdb0778c6fde0dc64f047ede4dece8615fce26f927c52aef907264e7a9bfd8
240 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1129 Execution through API

The sample is an OLE document with a critical heuristic indicating an embedded PE executable. High-severity heuristics for LoadLibrary and GetProcAddress APIs suggest dynamic library loading, common in malware execution. The document body contains mostly garbled text, but the presence of an embedded executable is the primary indicator of malicious intent, likely serving as a dropper for further malicious activity.

Heuristics 6

  • Embedded PE executable critical OLE_EMBEDDED_EXE
    MZ/PE header found inside document — possible embedded executable
  • PEB access via FS segment (x86) high SC_PEB_ACCESS
    PEB access via FS segment (x86)
  • Reference to LoadLibrary API high SC_STR_LOADLIBRARY
    Reference to LoadLibrary API
  • Reference to GetProcAddress API high SC_STR_GETPROCADDRESS
    Reference to GetProcAddress API
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 258,048 bytes but its declared streams total only 123,700 bytes — 134,348 bytes (52%) 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).
  • NOP-equivalent sled detected medium SC_NOP_EQUIV_SLED
    Long run of 0x61 bytes

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_office_0001ec00.exe
210653c79c7c7a76f6a3124e7e108e22b9c484435cf1b81abadc0b4b54207cca		 embedded-pe Office MZ+PE at offset 0x1EC00 132096 bytes

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