Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 73749fb5fff61a6d…

MALICIOUS

RTF / .DOC

73.5 KB First seen: 2023-10-13
MD5: be451318393f1e63f50da7560c946060 SHA-1: dc23e64d9873dd4ada187a6355dd04eb6c88a4b9 SHA-256: 73749fb5fff61a6d9d34171f0e70e62d5caa69127a12fb51059a7179f71bb1e4
160 Risk Score

Malware Insights

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

The file is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882) to execute arbitrary code. The embedded OLE object and the specific RTF heuristics strongly indicate exploitation of this known vulnerability. The document body, though partially encoded, discusses marketing strategies and consumer research, likely a lure to trick the user into opening the malicious content. The primary attack vector is likely through a spearphishing attachment.

Heuristics 4

  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000012e9.bin
00bc85e76d768761790894d0bf4276a265b7d71354d3d54bb189b0dec6de93bd
rtf-objdata-decoded RTF \objdata at offset 0x12E9 1915 bytes