Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 df9bb482c8a08241…

MALICIOUS

RTF / .DOC

32.2 KB First seen: 2023-04-28
MD5: 38e3bb8c7815cf5a32ff1af01400ed68 SHA-1: 72395f365ba535dfc3033116df66650727fa7575 SHA-256: df9bb482c8a082412101cd8697572ef66367b32a48876ee63f38a39b2c37b13a
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document that contains an embedded OLE object with a specific Equation Editor ProgID, indicating an attempt to exploit CVE-2017-11882. The ".objupdate" directive forces the OLE object to activate, triggering the exploit. The document also contains a lure instructing the user to 'Enable editing', a common tactic for macro-based or exploit-laden documents.

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_off000059a1.bin
682072db52b99a9ac0e332b1c9d8fec137faaf7cadbeabfab3694f5a78222fe0
rtf-objdata-decoded RTF \objdata at offset 0x59A1 1557 bytes