Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 b8e97f0e8beb7402…

MALICIOUS

RTF / .DOC

42.7 KB First seen: 2023-01-30
MD5: 8e890d6b47fa3c1939927d3dd101d1b5 SHA-1: e90f334aa67e040dd22af07f463a07386f73f74b SHA-256: b8e97f0e8beb7402eac9b99e4e2c5f747c641d8a1106210c2a27b0931c174927
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object with a critical Equation Editor vulnerability. The ".objupdate" directive indicates that the OLE object will be activated automatically upon opening, and the "SE_ENABLE_LURE" heuristic confirms the document instructs the user to enable content. This combination strongly suggests the document is designed to exploit the Equation Editor vulnerability to execute arbitrary code, likely 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_off00004199.bin
b6badf62834f8e3ccd64ed081b387bd62808a803923b994d66ec801327d4bdee
rtf-objdata-decoded RTF \objdata at offset 0x4199 2213 bytes