Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 84dae1821a11e803…

MALICIOUS

RTF / .DOC

77.2 KB First seen: 2023-10-20
MD5: d1c6f93835b8e863a87ce99294f33f06 SHA-1: ef2568304fa03773eeea81e5d897bcb21d7663fd SHA-256: 84dae1821a11e8030f97b65ab3de20e320e260b78b575e7da12ebb25a94c40b7
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic

The sample is an RTF document exploiting the Equation Editor vulnerability, indicated by the RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics. It contains an OLE object designed to be activated, likely to download and execute a secondary payload. The document body provides a lure related to financial audits, instructing the user to 'Enable editing' to bypass security measures.

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.
  • \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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00002668.bin
612d4c43d6e533b0f1de027cea5ccf94182d74f962489d3f82f79c8835930f0e
rtf-objdata-decoded RTF \objdata at offset 0x2668 2033 bytes