Malicious RTF — malware analysis report

Static analysis result for SHA-256 f0c11a5770045b52…

MALICIOUS

RTF

66.9 KB First seen: 2023-10-10
MD5: a3e323c2e911520862ae53f550c5de4a SHA-1: beaefa9b795fb61548f3e73ea8669310b1440d37 SHA-256: f0c11a5770045b52a0bfcc7133051b623916afdb3749de89adfb24471fa508ca
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1204.002 Malicious File T1059 Command and Scripting Interpreter T1059.005 Visual Basic

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor vulnerability. The ".objupdate" directive indicates an attempt to automatically activate the embedded object, and the "SE_ENABLE_LURE" heuristic suggests the document prompts the user to enable editing. This combination strongly suggests the file is designed to exploit the Equation Editor vulnerability to download and execute a secondary payload.

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_off000036b0.bin
8d12fdc9fb8278d24181efb0b7a24fd012b7a4e096f91c861516314a8a60ba74
rtf-objdata-decoded RTF \objdata at offset 0x36B0 1650 bytes