Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 dc306dbb15325c40…

MALICIOUS

RTF / .DOC

39.1 KB First seen: 2023-07-20
MD5: 47921ac5925698e152ca4c2563713a91 SHA-1: 6006ca65ecd53732dba75b862e61594706ee2c5c SHA-256: dc306dbb15325c40634f3089d5ff6dd9dae7b67c86215f5a3ded2f67aa0a7430
160 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object and specifically targets the Equation Editor, a known vector for exploits like CVE-2017-11882. The presence of \objupdate indicates an attempt to force activation of this embedded object. The document body includes a lure instructing the user to 'Enable editing', which is a common tactic to bypass macro security settings and trigger the exploit.

Heuristics 5

  • 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 1 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off00004411.bin
c819aea059bf9b738fcd14ec05860ca379e559d465af3730ff1b64b7acb36355
rtf-objdata-decoded RTF \objdata at offset 0x4411 1646 bytes