Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c89c86985789aa0e…

MALICIOUS

Office (OLE)

77.0 KB Created: 2016-05-09 21:39:00 Authoring application: Microsoft Office Word First seen: 2017-12-24
MD5: 8e0bcf5bed6882eb86132653493d681a SHA-1: 9b7816a37f5168fe5eb9fb551e71f4835658de95 SHA-256: c89c86985789aa0e21b889ae12f4867c31191f712b092c66b6a8e3ca22512096
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and contains a VBA macro that executes upon opening the document. The macro's obfuscated code, specifically the call to 'UhnZbJUv.gLkHiAeI' and 'RdzCgNLfo', suggests it's designed to download and execute a secondary payload. The presence of a 'Document_Open' macro and the 'SC_STR_WSCRIPT' heuristic further support this dropper functionality.

Heuristics 7

  • ClamAV: Doc.Dropper.Agent-6400486-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6400486-0
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 78,848 bytes but its declared streams total only 46,464 bytes — 32,384 bytes (41%) 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).
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Private Sub Document_Open()
Dim yhNrR As Boolean
  • 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) 494 bytes
SHA-256: ae603f41f99c0d4bc47a91cb9f461b53421c2ba9cacf8a05b0f1f47828cfb3b5
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
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
Private Sub Document_Open()
Dim yhNrR As Boolean
UhnZbJUv.gLkHiAeI
End Sub
Private Sub inmQympe()
RdzCgNLfo "45c7CSronwTbh4NcQbE2LK", "1EIfwxJKwwacUuZ652QKNgQH", False
cdVmY 1519, False, True
End Sub

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