Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 aa4e51ca5e13b798…

MALICIOUS

RTF / .DOC

31.8 KB First seen: 2022-11-18
MD5: b039aca3146e30bd04dc2b83c34f83a0 SHA-1: 4813bb50b9a10cbed58cb19331f480e191fe2349 SHA-256: aa4e51ca5e13b798a91225debfb2e4c751e0cfc0d63efc279fd9083c666cabbb
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object that exploits a known vulnerability in the Equation Editor. The presence of \objupdate indicates that the OLE object is designed to be activated automatically upon opening the document, which is a common technique for delivering malicious payloads. The document body itself is a lure, instructing the user to 'Enable editing' to view the content, further supporting a malicious intent.

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_off00005bf9.bin
211b13e15d793762af4bec77bb51f6b02fcb4942e21d026fdffe99cb15c75c76
rtf-objdata-decoded RTF \objdata at offset 0x5BF9 1994 bytes