Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 bb6685392a31dbdb…

MALICIOUS

RTF / .DOC

34.3 KB First seen: 2022-12-07
MD5: 458ba280517d61b4e52d257f791587ef SHA-1: 5ce50843c381ab1cdb84594dc3c6e428bff07674 SHA-256: bb6685392a31dbdb49c6a5d5be186d3cd991b3f3432fbde4a4122f4c3d095a61
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object that leverages the Equation Editor vulnerability. The ".objupdate" directive indicates that the object is designed to be activated automatically upon opening, likely to exploit the Equation Editor. The document body contains a lure instructing the user to 'Enable editing', which is a common tactic to bypass macro security settings and facilitate the execution of malicious code.

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_off00005a01.bin
7483599d05b679c1866d3df5cf6d83a84baceaec79fe5fc6833bc643575d19b0
rtf-objdata-decoded RTF \objdata at offset 0x5A01 1855 bytes