Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ebc6d9bdba2acb42…

MALICIOUS

RTF / .DOC

54.9 KB First seen: 2023-02-13
MD5: b53d29992533520b827228516f021f49 SHA-1: 9c2cfb272d01d95de2b38cc673253dd5dcc77af6 SHA-256: ebc6d9bdba2acb425f9ce0245b8b23c2b37f3ea7810dc3b8908d98e28dd27c01
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic T1566 Phishing T1566.001 Phishing: Spearphishing Attachment

The sample is an RTF document that exploits the CVE-2017-11882 vulnerability in the Equation Editor. The document body contains a lure instructing the user to enable editing and content, a common tactic for macro-based malware. The presence of ` tf_objdata` and ` tf_objupdate` heuristics further indicates the embedding and activation of OLE objects, which is characteristic of this exploit.

Heuristics 4

  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • \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_off000016d4.bin
c3f439d9a863d8d548b15aa72f1939f8a61b8438d1f094d8812032a3bbe67f67
rtf-objdata-decoded RTF \objdata at offset 0x16D4 3637 bytes