Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 53075ffa11d09556…

MALICIOUS

RTF / .DOC

33.0 KB First seen: 2023-05-11
MD5: 635b388aba446efd6d4c48c65cd2ed3d SHA-1: a026e0c484fcffe5e9d75b23da3562c377c84801 SHA-256: 53075ffa11d09556e2b2cce393dfe67255dfd0262f45cf9f529338706a6c1f98
180 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with a split ProgID, indicative of an Equation Editor exploit. The presence of \objupdate and a lure to 'Enable editing' strongly suggests the document is designed to trigger an exploit when opened. The embedded OLE object, objdata_00_off00004159.bin, is the primary artifact associated with this attack.

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_off00004159.bin
e081507a70c643984ba95872206c15dca91e78b695530a600888b6162640b426
rtf-objdata-decoded RTF \objdata at offset 0x4159 1570 bytes