Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9241c8b1633aa9b1…

MALICIOUS

Office (OLE)

992.2 KB First seen: 2015-09-19
MD5: 54d41b3d9004161b7aaa68d52fe59090 SHA-1: 13438511cab53836f51b6371db7b4d1621835aa7 SHA-256: 9241c8b1633aa9b14e98b4b64efcf447d91d80b3f414e6160649d88f23819f44
328 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1105 Ingress Tool Transfer

The file is identified as malicious due to the presence of an embedded PE executable and suspicious OLE structure. The VBA macros, while not containing executable statements themselves, are often used as a loader for embedded payloads. The embedded executable is the primary indicator of malicious intent, suggesting the document is a dropper for a second-stage payload.

Heuristics 8

  • ClamAV: Xls.Dropper.Agent-7377660-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7377660-0
  • Embedded PE executable critical OLE_EMBEDDED_EXE
    MZ/PE header found inside document — possible embedded executable
  • Embedded Office document has suspicious static findings critical EMBEDDED_OFFICE_CHILD_STATIC_TRIAGE
    A CFB/OLE Office document was found inside another file type and its carved contents matched Office exploit or payload heuristics. This catches wrapped exploit documents where the top-level file routes to a PE, archive, or generic scanner instead of Office.
  • 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 1,016,032 bytes but its declared streams total only 43,269 bytes — 972,763 bytes (96%) 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).
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • 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.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1271 bytes
SHA-256: 1393fb9c6c18f41eb0fa3c4533b46ef8e1670352e75321cc8504cd42cae698a3
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Attribute VB_Control = "ListView1, 1, 0, MSComctlLib, ListView"

Attribute VB_Name = "Sheet2"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Sheet3"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
embedded_office_000c2640.exe embedded-pe Office MZ+PE at offset 0xC2640 219808 bytes
SHA-256: 873e60018422e2c8a20b1d5b534934cc458c8a68ecbf86fccaad48197a4abc1c
embedded_office_off0000be40.ole embedded-office Embedded OLE/CFB Office body inside ole container at offset 0xBE40 967328 bytes
SHA-256: 62141f00221e31b5fb57124f71aeee57813f35ddd381923142e64b2b61300563

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