Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 71af0ab92ee4b7ce…

MALICIOUS

RTF / .DOC

13.1 KB First seen: 2023-03-16
MD5: e2b88d8ffa78d2305f067920e91e87bb SHA-1: 953598150265f73193542c28277aa07e4062df64 SHA-256: 71af0ab92ee4b7cef2a18809b84df07518b99060bd7f96bfe83521633e9635a5
140 Risk Score

Malware Insights

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

The file is an RTF document that exploits the Equation Editor vulnerability, indicated by the RTF_EQUATION_EDITOR heuristic. It also contains an objupdate directive, forcing OLE activation, and a lure to enable editing, suggesting it's designed to execute a payload. The document body discusses financial audits, a common social engineering tactic to trick users into enabling malicious content.

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_off00001c03.bin
77e28b113c3f3c189a7c9fd9d78c48503cddfeedd330a26d54b468ca1d013d09
rtf-objdata-decoded RTF \objdata at offset 0x1C03 1376 bytes