Malicious RTF — malware analysis report

Static analysis result for SHA-256 55ae80034c08e501…

MALICIOUS

RTF

25.3 KB First seen: 2022-11-09
MD5: 153b46a1977657e511eec4313e05246c SHA-1: 85dda9d7195af5e0f4369584c1d67a2444afb289 SHA-256: 55ae80034c08e501d764e57b170bb63243d55f14c22132031981a82904fe5072
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 PowerShell

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The presence of \objupdate indicates an attempt to automatically activate the embedded object upon opening. The heuristic SE_ENABLE_LURE suggests the document also contains a lure to trick the user into enabling editing or macros, which is a common delivery mechanism for exploits like this. The primary goal is likely to exploit the Equation Editor to gain initial execution, potentially leading to a secondary payload download.

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_off00004d96.bin
7f500f60c9f41fd42e9d1d7c20a846784734b10cf3df4b2f64df8e2519bf1180
rtf-objdata-decoded RTF \objdata at offset 0x4D96 1715 bytes