Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d1f3943abd9aabbc…

MALICIOUS

Office (OLE)

172.5 KB Created: 2020-05-13 06:24:01 Authoring application: Microsoft Excel First seen: 2020-09-07
MD5: 8810dfd90c2f6f69c352f5ac95b53b68 SHA-1: bc53e71b45f88ab2982ba0b121e4427abc4a9e7e SHA-256: d1f3943abd9aabbc7ab92a5f9c13cfa9c3a2c410595eda8cfa7f983626fa11cc
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. The macros utilize dangerous functions such as RUN, indicating an intent to execute arbitrary code. This is a common technique for downloading and executing secondary payloads, hence the classification as an unknown family downloader.

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) 130036 bytes
SHA-256: 8ec4b399fc0c2204d6446e034ceb98405c61cf4672b0923a9535dda2fe849c3f
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!FC15725 
' 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,JK15,"",574.50000000000000000000
'  Sheet,Q60,"",-0.24398625429553263966
'  Sheet,Z81,"",-304.00000000000000000000
'  Sheet,EU111,"",124.50000000000000000000
'  Sheet,FU112,"",-216.00000000000000000000
'  Sheet,IS137,"",-310.00000000000000000000
'  Sheet,HQ160,"",-90.00000000000000000000
'  Sheet,BE220,"",-275.00000000000000000000
'  Sheet,ID234,"",-4.06034382758620715492
'  Sheet,IB242,"",-1581.00000000000000000000
'  Sheet,JF266,"",-94.00000000000000000000
'  Sheet,HD273,"",50.00000000000000000000
'  Sheet,BK283,"",-0.80745341614906829264
'  Sheet,JM331,"",-0.07232913072329130721
'  Sheet,GY521,"",352.00000000000000000000
'  Sheet,GE549,"",175.00000000000000000000
'  Sheet,CJ557,"",-5.64444444444444481945
'  Sheet,DY566,"",191.50000000000000000000
'  Sheet,GW568,"",311.00000000000000000000
'  Sheet,HQ581,"",-1.00000000000000000000
'  Sheet,JR593,"",-185.00000000000000000000
'  Sheet,FX609,"",-5.11842105263157876038
'  Sheet,DS677,"",-130.50000000000000000000
'  Sheet,FK683,"",2.22727272727272707087
'  Sheet,CS703,"",-1.71428571428571419055
'  Sheet,IP708,"",111.50000000000000000000
'  Sheet,EX726,"",6.58823529411764674535
'  Sheet,GR772,"",2392.00000000000000000000
'  Sheet,FP833,"",153.00000000000000000000
'  Sheet,EA834,"",-0.27506426735218508783
'  Sheet,BN838,"",-101.00000000000000000000
'  Sheet,DX866,"",-4.66336633663366306735
'  Sheet,FE1027,"",133.00000000000000000000
'  Sheet,BP1037,"",-5.54166666666666696273
'  Sheet,CA1079,"",4.84905660377358493918
'  Sheet,GH1128,"",-212.00000000000000000000
'  Sheet,BE1138,"",-1.25465838509316762739
'  Sheet,JD1173,"",-1.75000000000000000000
'  Sheet,DY1202,"",-2.39639639639639634439
'  Sheet,FZ1388,"",7.66071428571428558740
'  Sheet,FS1448,"",339.00000000000000000000
'  Sheet,FI1450,"",-5.93877551020408134264
'  Sheet,BJ1453,"",-0.65217391304347827052
'  Sheet,HY1462,"",-136.00000000000000000000
'  Sheet,BG1480,"",2403.00000000000000000000
'  Sheet,JF1567,"",108.00000000000000000000
'  Sheet,FW1585,"",-340.00000000000000000000
'  Sheet,EH1624,"",3.03125000000000000000
'  Sheet,GE1641,"",-5.32000488281250039080
'  Sheet,JT1689,"",154.00000000000000000000
'  Sheet,DX1710,"",0.23809523809523808202
'  Sheet,DR1745,"",-0.07697412076974120831
'  Sheet,JA1748,"",-2.20588235294117662733
'  Sheet,JC1769,"",16.00000000000000000000
'  Sheet,EC1785,"",2362.00000000000000000000
'  Sheet,K1826,"",-4.18279569892473102044
'  Sheet,IU1840,"",40.49180327868852202755
'  Sheet,D1842,"",-0.54658385093167705104
'  Sheet,BF1883,"",359.00000000000000000000
'  Sheet,GA1988,"",-0.10615711252653928232
'  Sheet,HP1998,"",345.00000000000000000000
'  Sheet,FY2001,"",-84.00000000000000000000
'  Sheet,HO2032,"",0.04615384615384615641
'  Sheet,DX2074,"",-574.50000000000000000000
'  Sheet,DI2110,"",-0.13058419243986255087
'  Sheet,GE2123,"",0.13053613053613052908
'  Sheet,EZ2149,"",0.19940476190476191798
'  Sheet,DT2157,"",-3.36708860759493688874
'  Sheet,CN2162,"",-1.20000061035156257994
'  Sheet,HE2300,"",187.00000000000000000000
'  Sheet,C2302,"",316.00000000000000000000
'  Sheet,BH2409,"",2379.00000000000000000000
'  Sheet,II2421,"",318.00000000000000000000
'  Sheet,FP2449,"",-0.16141732283464566011
'  Sheet,P2517,"",0.98000061035156249556
'  Sheet,IT2519,"",-0.94705882352941173075
'  Sheet,JO2615,"",-1.82954545454545458583
'  Sheet,GF2637,"",-2358.00000000000000000000
'  Sheet,CI2742,"",-341.00000000000000000000
'  Sheet,S2782,"",-92.00000000000000000000
'  Sheet,N2789,"",0.06666666666666666574
'  Sheet,JT2814,"",-0.11311053984575834830
'  Sheet,GG2853,"",8.81506849315068485851
'  Sheet,DM2871,"",-7.47058823529
... (truncated)