Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 4513b9baa2b09aa7…

MALICIOUS

RTF / .DOC

45.6 KB First seen: 2023-09-06
MD5: 1b63f096abb75afaa481091f516e84cf SHA-1: 54bf89eb5f7af35d2cc796f5d77dc06f00d19b71 SHA-256: 4513b9baa2b09aa75a0c0e4aad28ba92b746bd8ed6dc3af47eabcc5f31ae93a5
140 Risk Score

Malware Insights

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

The sample is an RTF document that exploits the Equation Editor vulnerability (RTF_EQUATION_EDITOR). It contains a lure text about financial auditing to trick the user into enabling editing and macros (SE_ENABLE_LURE). The presence of OLE object data and the ".objupdate" directive strongly suggest that the document is designed to activate embedded objects, likely 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.
  • \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_off00003691.bin
f7699a77b59ec80435fc0914428087d7b0e8a76a265bd6b5c9a32fff990318d9
rtf-objdata-decoded RTF \objdata at offset 0x3691 1368 bytes