Malicious RTF — malware analysis report

Static analysis result for SHA-256 b1e269b5ffde3ba6…

MALICIOUS

RTF

1.57 MB First seen: 2022-09-12
MD5: b3cdbf24ffe6e026cd58e6806e877a72 SHA-1: 6238d897d053c5894fc48ea905a3da2607f73047 SHA-256: b1e269b5ffde3ba61d1ff273519393e06f1690f069c71e7dfdb1b590039df511
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF file contains multiple indicators of exploitation, specifically related to CVE-2017-11882 through the Equation Editor. The presence of OLE objects and the \objupdate directive strongly suggest that the embedded Equation Editor object is designed to be activated, leading to the execution of arbitrary code. The decoded object data likely contains a secondary payload or script, although the full content is truncated. The heuristics indicate a critical vulnerability exploitation.

Heuristics 5

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000012b8.bin
82f71250fc4bfab145e45c80654ab69b444182cb555ef74d5837e04d8555fb75		 rtf-objdata-decoded RTF \objdata at offset 0x12B8 81922 bytes
objdata_01_off0002f454.bin
f7b929ce489dfb0e55f3383a35fdd691eace09a148b71bdce40ecf74b197fdc5		 rtf-objdata-decoded RTF \objdata at offset 0x2F454 346461 bytes

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