Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1f638a94c7425ece…

MALICIOUS

RTF / .DOC

35.9 KB First seen: 2023-05-31
MD5: 84c585cb3ee2c73faa4be1f21db24aaf SHA-1: c1e5ce404b89c3dfb7e6c041fb5fb7b0eb96d0da SHA-256: 1f638a94c7425ece6b51870d19b6feffb9c990b8a803ce201d6144436f394522
180 Risk Score

Malware Insights

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

The sample is an RTF document that uses an Equation Editor exploit, indicated by the RTF_EQUATION_EDITOR heuristic. It also employs a lure to enable editing and macros, a common technique for malware droppers. The embedded OLE object data and automatic linking further suggest malicious intent, likely to execute a secondary payload.

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.
  • 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_off0000504b.bin
1cd2d59c1629fb19693229af1a3813494113d81d698af6ad30c5da83bc06150b
rtf-objdata-decoded RTF \objdata at offset 0x504B 1978 bytes