Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 dcd3be4cad70f537…

MALICIOUS

RTF / .DOC

37.3 KB First seen: 2023-04-15
MD5: c44e65963eccd86119772a8b1e32f518 SHA-1: ea9c40e3ead633f0798ed7c91b9c27205e616ee3 SHA-256: dcd3be4cad70f5371e2ad3c3112c5faac92a9fff645c25cc5369556ebc5adadd
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 embedded OLE object is the primary indicator of a potential exploit, likely leading to further stages of infection.

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_off00005ad1.bin
a4bde752c3d4415cc3bb92bf4b4d55e819d46afac944243ce49c41abcb2b2ef3
rtf-objdata-decoded RTF \objdata at offset 0x5AD1 1666 bytes