Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 98910185a8f23d40…

MALICIOUS

RTF / .DOC

2.89 MB First seen: 2022-08-01
MD5: ca88200dadc8fe4072cc169697383ed3 SHA-1: 990cefe8b6c86e0532e272c6a11f7fa6ae77cef9 SHA-256: 98910185a8f23d4029ed11d2af3e4d4df92587d600834e7c87caea8e969928b6
382 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1559.002 Component Object Model Hijacking T1059.001 PowerShell

The RTF document contains multiple indicators of exploitation, including OLE object data, an Equation Editor ProgID, and evidence of CVE-2017-11882 exploitation. The presence of a PE header within the hex-encoded data suggests that a malicious executable is embedded and likely dropped. ClamAV also detected this file as Rtf.Dropper.Agent-9965975-1, further supporting its malicious nature as a dropper.

Heuristics 10

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • 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.
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • ClamAV: Rtf.Dropper.Agent-9965975-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-9965975-1
  • \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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~2302KB of hex-encoded data inside \objdata sections — may hide a payload
  • 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
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000012ab.bin
e72cfea291b0873551c9ab4ddc6efb36b3ae271976accff32b15a52d95641b60
rtf-objdata-decoded RTF \objdata at offset 0x12AB 1156933 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.83, consistent with packed or encrypted content.
objdata_01_off0023c2c0.bin
e4325f0b75b454ccfb493d6255ccd046928a3bef6811edf39a31e79146bf33a5
rtf-objdata-decoded RTF \objdata at offset 0x23C2C0 141152 bytes