Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 56e360938ccd51c7…

MALICIOUS

RTF / .DOC

1.72 MB
MD5: 22224db932c9a2057e44a71641f67bf9 SHA-1: b73f2c0e6d3a7553a2d3c096e21beab676542e25 SHA-256: 56e360938ccd51c75a5ddb14a967cf0ab0daa6efb56f499d27d8db1f5e0316e0
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Phishing: Spearphishing Attachment T1059 Command and Scripting Interpreter

The sample is a malicious RTF document containing an embedded OLE object with the Equation.3 ProgID, which is the primary delivery mechanism for CVE-2017-11882 and CVE-2018-0802. The presence of  objupdate forces automatic activation of the object, ensuring the execution of the payload embedded within the OLE object. While the exact CVE attribution is not possible due to the missing MTEF record, the overall structure and the presence of a PE-like payload (mz_offset=0x18558) indicate a clear intent to achieve remote code execution.

Heuristics 5

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact 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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1806KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003b.bin
8456111998a293e68f45fdf8fe56310d46a9b5a3ace07ac06c89a23708e30b53		 rtf-objdata-decoded RTF \objdata at offset 0x3B 903400 bytes

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