Malicious RTF — malware analysis report

Static analysis result for SHA-256 a07f99d172177fd1…

MALICIOUS

RTF

1.45 MB
MD5: d2ac671c02b71ff9af6dfad349918a4c SHA-1: d9c5616c9d2b4edfdc665ffe44b808eb619e5ccb SHA-256: a07f99d172177fd14a46670bce08fb1eda07a046743d8a563cf66f7cc385662f
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF file contains embedded OLE objects and specifically triggers the Equation Editor vulnerability, indicating it's designed to exploit this known weakness. The ".objupdate" directive suggests that the embedded OLE object is automatically activated upon opening the document. The extracted document body contains obfuscated VBA-like code that appears to manipulate strings and potentially download or execute further stages, though the exact functionality is obscured. This points to a classic exploit delivery mechanism.

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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001269.bin
ea5924c5ecc3343aba1402622084c0716d9e14c592bceb5112fa45ab31109050
rtf-objdata-decoded RTF \objdata at offset 0x1269 13607 bytes
objdata_01_off00008ddf.bin
c76143411a64e196bc874d749764d9bc501945a5ef088579e6fdfcc29cce7a83
rtf-objdata-decoded RTF \objdata at offset 0x8DDF 275202 bytes