Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1660188dc402d5e7…

MALICIOUS

RTF / .DOC

3.9 KB
MD5: a125d90523a73432f8faa7de66384c75 SHA-1: e754f0874a2b23037701f21f7a14e33ddf55d9ec SHA-256: 1660188dc402d5e73071058e60a083b15d3f21b22b6c501a450d422831de4cc0
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains embedded OLE object data and specifically triggers the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for the execution of arbitrary code upon opening the document, likely leading to the download and execution of a secondary payload. The presence of ".objupdate" further indicates an attempt to force OLE object activation.

Heuristics 5

  • 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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000096.bin
631490edcb06e6f742eb0f8daee6dcb99f2d16af09bf9574eb1d0fd662cc120d
rtf-objdata-decoded RTF \objdata at offset 0x96 1760 bytes