Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5288eacf1129499e…

MALICIOUS

RTF / .DOC

39.1 KB First seen: 2023-02-09
MD5: a8c9121e6ee657a0451f4eeb6e6865c6 SHA-1: 077d52772505c22f0123e53323dc6fefdfc11ed3 SHA-256: 5288eacf1129499ed565c4b506f60d8f6bd6d7f5c4e6d7b39eb87d98b6ac1914
140 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with a specific Equation Editor ProgID, triggered by an \objupdate directive. This strongly suggests an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882) to execute arbitrary code. The document also contains a lure to enable editing, a common tactic for macro-based malware.

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_off000051a7.bin
a49da5721beb57b11a34dc7ccbf9e4afc29944998cb2915fc92f3da9bdb0ec54
rtf-objdata-decoded RTF \objdata at offset 0x51A7 1780 bytes