Malicious RTF — malware analysis report

Static analysis result for SHA-256 74919e63b52bac82…

MALICIOUS

RTF

105.6 KB First seen: 2024-11-01
MD5: cf58c7b5d98dd33089c58f9edb28c944 SHA-1: 2506526682b8a0f7a41dee1745125bd2689850fa SHA-256: 74919e63b52bac82cbb4154415ba6fcdc124c1d06e4b044086be1bb3b1b5a5e3
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1204.002 User Execution: Malicious File

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability (CVE-2017-11882). The presence of RTF_OBJAUTLINK and RTF_OBJUPDATE heuristics indicates that the embedded object is designed to be automatically activated upon opening the document, leading to code execution. This is a common delivery mechanism for malware, often used to download and execute a secondary payload.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001e90.bin
4e66e92ba3e890748e3e45d18299220fc87c1726c7353d2ef8f3096a3f755d88
rtf-objdata-decoded RTF \objdata at offset 0x1E90 1990 bytes