Malicious RTF — malware analysis report

Static analysis result for SHA-256 9b1195da0384083a…

MALICIOUS

RTF

37.1 KB First seen: 2023-07-18
MD5: aed387c2000a4a37308a90431ddf9070 SHA-1: 7a94e6c33ac6d0d3a0f548c63c79d1ae3868b222 SHA-256: 9b1195da0384083aa583b862ca6f9c1397c5ae162f15576d37ebd40dbbdd1e73
160 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object, specifically targeting the Equation Editor, and uses an \objupdate directive to force activation. The document body includes a lure instructing the user to 'Enable editing' to view the content, which is a common tactic for macro-based malware droppers. The presence of RTF_EQUATION_EDITOR and SE_ENABLE_LURE heuristics strongly suggests an exploit attempt via the Equation Editor vulnerability.

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_off000053a4.bin
79c6ab4a39710836952f71e1fee06eff286d4a0abc77532d7e2f59b6bd6d1815
rtf-objdata-decoded RTF \objdata at offset 0x53A4 1248 bytes