Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 817841a2514c14cc…

MALICIOUS

RTF / .DOC

30.9 KB First seen: 2022-12-06
MD5: 422423407890fea4b33d4502165c8747 SHA-1: 6e2a3dcf555b891970e6d4ecd09c8a18fa6f00c5 SHA-256: 817841a2514c14cc2951a19a7353ea6124feb4b6f991f5c2d77a9861a63f01e9
140 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with an Equation Editor ProgID, which is a known exploit vector. The ".objupdate" directive forces OLE activation upon opening, and the document body contains a lure instructing the user to 'Enable editing'. This combination strongly suggests an exploit targeting a vulnerability in Equation Editor for initial execution.

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_off00005087.bin
61ea760823d03162bd4c85e2bb0103811b2c7048a807b24f1cc70b448bffb9ca
rtf-objdata-decoded RTF \objdata at offset 0x5087 2007 bytes