Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0d3d678e767b0617…

MALICIOUS

RTF / .DOC

259.0 KB First seen: 2023-07-14
MD5: 43d1b5279f788cda7baacf55237ed5fe SHA-1: ee2204fd29ee9599ec2991be46a52d36cda5d55f SHA-256: 0d3d678e767b06171022cdb1d9997257078f75de7070b7e9fa620eea7629647d
160 Risk Score

Malware Insights

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

The RTF document contains multiple indicators of exploiting the Equation Editor vulnerability, including \objdata, \objupdate, and a split ProgID. This exploit is commonly used to deliver a second-stage payload, likely a downloader, which would then fetch and execute further malicious content. The presence of OLE object data further supports the exploitation of embedded objects within the document.

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_off00001a37.bin
ce62443b1b94a60143139482d8869e23e56c846c9a3d0fd8bbfb79746142791d
rtf-objdata-decoded RTF \objdata at offset 0x1A37 77697 bytes