Malicious RTF — malware analysis report

Static analysis result for SHA-256 37eea48ab368f67c…

MALICIOUS

RTF

31.2 KB First seen: 2023-07-06
MD5: 492aadf83dc7f018a4328b5d6aed4123 SHA-1: c1d199c5e7ea26e16b7812bb1cf4c44a1cddb84c SHA-256: 37eea48ab368f67c8303e409efdd35a9f8075eed7b3ef130738b74f2af3ec0c1
180 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object with a ProgID indicative of the Equation Editor vulnerability (CVE-2017-11882). The presence of \objupdate and SE_ENABLE_LURE heuristics indicates the document attempts to trick the user into activating the object, likely leading to the execution of a second-stage payload. No specific family could be identified, but the attack pattern is consistent with a downloader exploiting a known Office vulnerability.

Heuristics 5

  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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_off0000503d.bin
c0001b71bf3b8c5bfc24b822825191d5f397f3123b1f203a7b41e7f5f110b6cc
rtf-objdata-decoded RTF \objdata at offset 0x503D 1912 bytes