Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 fd0ce443be0ee708…

MALICIOUS

RTF / .DOC

30.6 KB First seen: 2023-01-06
MD5: 1f7923e28a28f090b0ae3315826c43bf SHA-1: b75dac8169d88f0fec257e5e5bf4a501f33f11b4 SHA-256: fd0ce443be0ee708e3a1cec9ca7750f8383663f39022ed54eb3f23d90fd433da
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution: Malicious File T1059 Command and Scripting Interpreter

The file is an RTF document containing an embedded OLE object that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This vulnerability allows for arbitrary code execution when the object is activated, which is triggered by the \objupdate directive. The document also contains a lure instructing the user to 'Enable editing', a common tactic for macro-based malware.

Heuristics 6

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • 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_off0000574c.bin
c45aaaa10af457aea2647cc4df23175b1829bdc933c7c763dbf6689ee8c716bd		 rtf-objdata-decoded RTF \objdata at offset 0x574C 1615 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.