Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 cb46af1427bb42b0…

MALICIOUS

RTF / .DOC

34.1 KB First seen: 2023-05-25
MD5: f8f0d8043ba8f2ffa971c6ac9463ab22 SHA-1: e03db3b3ba7ccbf7bc441c7b2c1745f98430e821 SHA-256: cb46af1427bb42b05cf4ca684f2cce83c56d42ac011f42eb8dd6ab799106664f
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File T1059.005 PowerShell

The RTF document contains an embedded OLE object with a split Equation Editor ProgID, a known exploit technique. The 'SE_ENABLE_LURE' heuristic indicates the document prompts the user to enable editing, which would activate the OLE object. This strongly suggests the file is designed to exploit a vulnerability, likely CVE-2017-11882, to download and execute 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_off000042eb.bin
26baa2496cc2a45495bb255102c531d1de1706dc0de521130d0cf8ed3b13564a
rtf-objdata-decoded RTF \objdata at offset 0x42EB 1628 bytes