Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 a7614fc60dc6d7a6…

MALICIOUS

RTF / .DOC

34.1 KB First seen: 2023-02-08
MD5: 924af368f685901a7b0de2f91b7d1cf4 SHA-1: 41812cad0eab6829e8f7425cecde71e00d850d1d SHA-256: a7614fc60dc6d7a6e65657d39b14ed933ae3fdfec08f53449bc55368f5df1d6c
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 that contains 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 body includes a lure to 'Enable editing', a common tactic to bypass macro security. The primary goal is likely to exploit this vulnerability to download and execute 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_off0000475c.bin
8b83200f539c0b18e4b37767d7a955fc9acd535dafc62ae2a4de52445a27a969
rtf-objdata-decoded RTF \objdata at offset 0x475C 1576 bytes