Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 70cccfd28bad2293…

MALICIOUS

RTF / .DOC

66.4 KB First seen: 2023-08-07
MD5: c5b0b4e64f077076496caac633a53140 SHA-1: d67d41e450bf621f4fd9f5b7c25b277e92110ad1 SHA-256: 70cccfd28bad2293746e594553271daf4cfa428efb56eed9f8be1cd4c1b5fe21
180 Risk Score

Malware Insights

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

The sample is an RTF document exploiting the Equation Editor vulnerability (RTF_EQUATION_EDITOR) and using OLE object data (RTF_OBJDATA) with automatic linking and update triggers (RTF_OBJAUTLINK, RTF_OBJUPDATE). The document body contains a lure text discussing financial audits and prompts the user to 'Enable editing', indicating a social engineering tactic to bypass security measures and execute the embedded malicious OLE object.

Heuristics 5

  • 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
  • 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_off00004164.bin
73f844facf4ef752228ca92f6ed0cf20b86ee6fee16b085d52fd9dfa10a233ad
rtf-objdata-decoded RTF \objdata at offset 0x4164 1670 bytes