Malicious RTF — malware analysis report

Static analysis result for SHA-256 47843761ef2672b9…

MALICIOUS

RTF

1.05 MB First seen: 2022-08-31
MD5: 9197f02c21aba9c983dfb5e480b856ce SHA-1: 292ee1fee41b4ee3c8611917430335f4864f4c7d SHA-256: 47843761ef2672b9609f9d8bf89bd8eb9e5e8ac829a5049c6ea5ed238fe3118a
180 Risk Score

Malware Insights

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

The RTF document contains embedded OLE objects, specifically triggering the CVE-2017-11882 vulnerability through the Equation Editor. This exploit allows for the execution of arbitrary code, likely to download and run a secondary payload. The presence of OLE object data and specific Equation Editor-related heuristics strongly indicates this attack vector.

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_off000012ab.bin
511cc625c4aa7442e769cdc846ae81f40df56d8eacd535bcb865dd291a0260ee		 rtf-objdata-decoded RTF \objdata at offset 0x12AB 76393 bytes
objdata_01_off0002c908.bin
e1fc1a4c0e67e69e3fb71023b7446271b7980a05bfadf3f1c66142aaf4530e1c		 rtf-objdata-decoded RTF \objdata at offset 0x2C908 187172 bytes

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