Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c178c62b3cfc7af6…

MALICIOUS

RTF / .DOC

36.3 KB First seen: 2023-02-06
MD5: e817179cffeac3baf3e51452316d2c62 SHA-1: e63b88c239aa071085ccc210b23b32d4518f7095 SHA-256: c178c62b3cfc7af6965875631c782f2dc1f0b3d49cd9b2cf6b84358cb6cb651a
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 split Equation Editor ProgID, a known exploit technique. The ".objupdate" directive forces OLE activation, and the document body contains a lure instructing the user to 'Enable editing'. This combination strongly suggests an exploit targeting the Equation Editor vulnerability to deliver a malicious 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_off00005477.bin
825f401df951374e075dc807a1ad5285b0245eca7faf26aadf1c1985b96df98a
rtf-objdata-decoded RTF \objdata at offset 0x5477 1494 bytes