Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 90c7a131f11a2e54…

MALICIOUS

RTF / .DOC

28.7 KB First seen: 2023-04-24
MD5: 9d09b6e9bf068e83c78afe33f9857c7b SHA-1: ad5661ad76c507cc12a402149734ea0648bfcca2 SHA-256: 90c7a131f11a2e5450a63faac63226a405fe42398f13db2e1b352a3eeba4ad2b
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object that exploits a vulnerability in the Microsoft Equation Editor. The document body contains a lure instructing the user to 'click Enable editing', which is a common technique to bypass macro security settings and trigger the exploit. The exploit likely leads to the execution of a secondary payload.

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_off00003488.bin
3771ca476b9d8ba8098471a30cff4edd3d9abafeecc6ec066d5d7c7138fb909e
rtf-objdata-decoded RTF \objdata at offset 0x3488 1401 bytes