Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 529c5ffa3f2d23ea…

MALICIOUS

RTF / .DOC

38.9 KB First seen: 2023-05-17
MD5: 47ac0b571958ae0a91962c944d2a50dd SHA-1: e67bc9a25e25c70539531dcb97c5e129c04d39fd SHA-256: 529c5ffa3f2d23ea1961416c763f2a667de2407c3812f9f16c191f5795dbcf16
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1204.002 Malicious File T1059 Command and Scripting Interpreter T1059.005 Visual Basic

The file is an RTF document containing an embedded OLE object, specifically targeting the Equation Editor vulnerability. The document body includes a lure instructing the user to 'Enable editing', a common tactic to bypass macro security. The presence of RTF_OBJUPDATE and RTF_EQUATION_EDITOR heuristics strongly suggests an attempt to exploit this vulnerability, likely leading to the download and execution of a secondary 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_off00004652.bin
38e9be97f4594b903dd082608739c6911512daf640ce16cfac40716e8a106b19
rtf-objdata-decoded RTF \objdata at offset 0x4652 1958 bytes