Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e2dde83360d72f5c…

MALICIOUS

RTF / .DOC

7.5 KB
MD5: 4f2dedd5116872d6b9c948110fd0935d SHA-1: ba45703172ec49c13b78b148b0ff4bd9705d314b SHA-256: e2dde83360d72f5c0bccc2ee660730a7975ad1afb68688feadfbb7c89c253651
120 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.001 PowerShell T1204.002 Malicious File

The RTF document contains an embedded OLE object that leverages the Equation Editor vulnerability (CVE-1997-2455 or similar). The ".objupdate" directive indicates that the OLE object is designed to be activated automatically upon opening the document, which is a common technique for exploiting this vulnerability. The heuristics strongly suggest this is a delivery mechanism for a secondary payload, likely executed via PowerShell given the commonality of this technique.

Heuristics 3

  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000d35.bin
bb2d15d784e356e5baafcbae73e3c80ab9f33ecdf5244a6db90e96618a51c6b2
rtf-objdata-decoded RTF \objdata at offset 0xD35 1529 bytes