Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6a82ae3766ed5c9d…

MALICIOUS

RTF / .DOC

25.8 KB First seen: 2022-12-23
MD5: 939fb121a70d208952ee9682d01a5283 SHA-1: 8dae00a507bd100d6219c274aacb729785aefac6 SHA-256: 6a82ae3766ed5c9d12b7bb1505bbd2d9ef5aae8c5d2a50ccc44cce19839e745e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object that exploits a known vulnerability in the Microsoft Equation Editor. The ".objdata" section and the ".objupdate" directive indicate that the embedded object is designed to be activated, likely triggering the Equation Editor exploit. The heuristic "SE_ENABLE_LURE" suggests the document also contains social engineering to prompt the user to enable editing, further facilitating the exploit execution.

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_off00004ab9.bin
8bb7f0ac8d5c3fce617e72c46d277b8f1ea1ba412a278a2f6adc6be6b33cd420
rtf-objdata-decoded RTF \objdata at offset 0x4AB9 1605 bytes