Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e9cdff48a897c8c2…

MALICIOUS

RTF / .DOC

36.1 KB First seen: 2023-04-04
MD5: 083fe85feaca3c287422b140b6800369 SHA-1: 4d80fbe98e042a96e8bee8fbca3bbac97b7dac81 SHA-256: e9cdff48a897c8c270c37c6a6b4491b8665834201fa4f5ee0674abc45ac0b4d2
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 that contains an embedded OLE object with a specific Equation Editor ProgID, indicating an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882). The \objupdate directive further suggests that the embedded object is designed to be activated automatically. The document body contains a lure to 'Enable editing', a common tactic to bypass macro security. The primary goal is likely to execute a malicious payload via the Equation Editor 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_off00004f0a.bin
0eaa275ac3f3fb1e23ab6e29b187edbf12c866053bb9b3f50b388d85455172ca
rtf-objdata-decoded RTF \objdata at offset 0x4F0A 1849 bytes