Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 a013b58fe776a005…

MALICIOUS

RTF / .DOC

27.1 KB First seen: 2022-11-04
MD5: 8ca310a91c7e567a8169cc8df74383b0 SHA-1: 1d90e7c83f9919494ed9f3725e900474b95d5573 SHA-256: a013b58fe776a00561f91facfb16975ee0677d81cea1f43814b465403abf5fdb
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object that exploits a known vulnerability in the Equation Editor component of Microsoft Office. The presence of \objupdate indicates an attempt to automatically activate the embedded object, which is a common technique for exploiting this vulnerability. The document body contains a lure to 'Enable editing', further suggesting a malicious intent to bypass security measures and execute an exploit.

Heuristics 4

  • 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
  • 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_off000054a7.bin
760bea284262078c509b91d8d0effdc04f51bdfb5738ce57305b47a1115f2685
rtf-objdata-decoded RTF \objdata at offset 0x54A7 1491 bytes