Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 47b3c27cc1944227…

MALICIOUS

RTF / .DOC

24.1 KB First seen: 2023-01-26
MD5: a8e42c745bfdb34e46258c9bb41c7cbe SHA-1: 6a72671d488c40b49219b075753ee8d5f8860eb1 SHA-256: 47b3c27cc19442278a032878ac5f46e5e0c6ac9fc730aadfe7ae06242f6a3b43
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 with a specific Equation Editor ProgID, indicating an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882). The \objupdate directive further suggests that the OLE object is designed to be activated automatically. The document also contains a lure instructing the user to 'Enable editing', a common tactic for macro-based malware delivery. No scripts were extracted, but the presence of the exploit and lure strongly suggests a malicious intent to download and execute a second-stage 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_off0000460c.bin
ee3a882a5f790e66a9039dccffedfea2ee5bd84a912bdce35139220f251b9743
rtf-objdata-decoded RTF \objdata at offset 0x460C 1898 bytes