Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 aca59f0c799782c1…

MALICIOUS

RTF / .DOC

45.9 KB First seen: 2023-07-28
MD5: 0c99557a08deccedae397186b8b6cd26 SHA-1: d35ada30f913d23f7d6f81bb45ac0a916c6ebfbb SHA-256: aca59f0c799782c11cb0429e0ba68a78368faac1e23397253e0b8375a242883c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 User Execution T1059.005 Service Execution

The RTF document contains embedded OLE object data and specifically targets the Equation Editor, a known vector for exploits. The presence of \objupdate and a lure to 'Enable editing' strongly suggests an attempt to trigger an exploit. The document body itself appears to be legitimate academic content, indicating the lure is likely a cover for the malicious 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_off000043dc.bin
262698b52a10570b3af5204c96e2d21d5f1db48caa8c260fce4357fafcd9e1a7
rtf-objdata-decoded RTF \objdata at offset 0x43DC 1729 bytes