Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 d6b0c09b22628661…

MALICIOUS

RTF / .DOC

20.0 KB First seen: 2023-03-14
MD5: 8411fcb597beeab1322537a88bce1697 SHA-1: 48dac157bed3eaeb6109d362028497106ea3f73d SHA-256: d6b0c09b22628661d848658d1891d4596171a9cf1a2d6e8c0cbb3b52847ebf8d
160 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 that leverages OLE object embedding, specifically targeting the Equation Editor vulnerability. The document body contains text designed to appear legitimate about financial auditing, while a heuristic indicates a lure to enable editing and macros. This combination strongly suggests the document is a dropper intended to exploit the Equation Editor vulnerability to execute a malicious payload.

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_off00003544.bin
d38953ac4de537641f422a0ae4bdd69380693a1b1b1c73589c8cf9e010c0497b
rtf-objdata-decoded RTF \objdata at offset 0x3544 1515 bytes