Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1184b8a3e34bfdc5…

MALICIOUS

RTF / .DOC

44.0 KB First seen: 2022-10-14
MD5: 7ba797089349e16debd1a2acaafd74ad SHA-1: 20ac9949d6053f80a3bfe0638d691c749a31234f SHA-256: 1184b8a3e34bfdc59cec5ec4348fec8ed07dce1976357dcc5ac35eca45089a3b
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The file is an RTF document containing a malicious OLE object, specifically identified as related to CVE-2017-11882 and using the Equation Editor. The presence of `RTF_EQUATION_EDITOR`, `CVE_2017_11882_ACTIVATION_RELATED`, and `RTF_OBJAUTLINK` heuristics strongly indicates exploitation of this vulnerability. The `SE_ENABLE_LURE` heuristic suggests the document prompts the user to enable content, a common tactic for malware droppers. The embedded OLE object is the primary indicator of compromise.

Heuristics 6

  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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 1 \objdata section(s) — embedded OLE objects
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000016d8.bin
92385433a3143b625a296de45591c2929bbe43b3573f5bff91813dd5456e7faa		 rtf-objdata-decoded RTF \objdata at offset 0x16D8 1590 bytes

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