Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 12fb29627d448762…

MALICIOUS

RTF / .DOC

25.7 KB First seen: 2023-01-24
MD5: 7b5bdfb5b48465cce4bca305226f08a1 SHA-1: 019e709b5b6c7368d134b33c0cc18d9f6242e392 SHA-256: 12fb29627d4487623d251e861e576e86b6f2205f7fc44ba29301d9ecd60d6760
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 specific Equation Editor ProgID, as indicated by the RTF_EQUATION_EDITOR heuristic. The RTF_OBJUPDATE heuristic suggests that the document attempts to automatically activate this object upon opening, which is a common method for exploiting vulnerabilities like CVE-2017-11882. The SE_ENABLE_LURE heuristic confirms the presence of a prompt to 'Enable editing', further supporting the attack vector of social engineering to trigger the exploit.

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_off0000509c.bin
a9532da7abab3e0981fe1ed7f44a4cca76e0be1e508dbae841126c9dbc5ddb53
rtf-objdata-decoded RTF \objdata at offset 0x509C 1609 bytes