Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8595dff2fcb694f3…

MALICIOUS

RTF / .DOC

24.9 KB
MD5: aefa66647cfe2b49769b36b222af2f92 SHA-1: b6a92974cc49480f15daea5867f5a3fd0f9bbb3c SHA-256: 8595dff2fcb694f3ee6c56c41ac2ea22d8e25d2d96c17c21b3c3ea922d35c885
120 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document that leverages the Equation Editor vulnerability. The presence of \objdata and \objupdate heuristics strongly suggests the embedded OLE object is designed to be activated, likely leading to the exploitation of CVE-2017-11882. This exploit is commonly used to download and execute a second-stage payload, making the primary attack pattern a document-based exploit leading to remote code execution.

Heuristics 3

  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001a1c.bin
8c0ee7d0e16ea7afbc7de14b279859221aa6839255b5df2234a3d56ff06963dd
rtf-objdata-decoded RTF \objdata at offset 0x1A1C 1835 bytes