Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7af5cf2c2851627f…

MALICIOUS

RTF / .DOC

30.6 KB First seen: 2023-03-28
MD5: 685c4cd21e27467ff893f2f5365ef566 SHA-1: 25ca8c8ef3c305d207367bbe15f7625fd1e236e2 SHA-256: 7af5cf2c2851627fffce58f36ad4eaa1b95f87eec61c206d043d916d12b3d36b
160 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 that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The presence of the \objupdate directive indicates an attempt to automatically activate the embedded object, likely to trigger the exploit. The 'SE_ENABLE_LURE' heuristic suggests the document contains text prompting the user to enable editing or macros, a common social engineering tactic to bypass security measures.

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.
  • \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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off000051d9.bin
58996c322209fdfc13e66e12f3411fb30b4c1c684f81ec415212fa1a52b1e47f
rtf-objdata-decoded RTF \objdata at offset 0x51D9 1729 bytes