Malicious RTF — malware analysis report

Static analysis result for SHA-256 2a871ffb84aa66cd…

MALICIOUS

RTF

13.9 KB First seen: 2022-10-04
MD5: 5f4e78396958c7e9add7060c17cd448d SHA-1: fbfdb89444e4bcec86d7599bf7c85c7f07f0bfc9 SHA-256: 2a871ffb84aa66cd0d0a2d030e979f35d0bc1f96fcb60248839dd9a488edd109
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1566 Phishing T1566.001 Phishing: Spearphishing Attachment T1566.002 Phishing: Spearphishing via Service

The file is an RTF document containing an embedded OLE object, specifically targeting the Equation Editor vulnerability. The document body contains a lure instructing the user to 'Enable editing' to view the content, which is a common technique to bypass macro security settings and execute malicious code. The presence of RTF_OBJDATA, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics strongly suggests exploitation of an OLE object vulnerability within the Equation Editor.

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_off0000180e.bin
823e34687972c89a0f48223f049607eded8fbaf82237873d1b6bbe46b0cf061a
rtf-objdata-decoded RTF \objdata at offset 0x180E 1482 bytes