Rtf.Dropper.Agent-9965975-1 — RTF malware analysis

Static analysis result for SHA-256 d64b5395abe1d3f3…

MALICIOUS

RTF

2.83 MB First seen: 2022-08-16
MD5: e903687f6ac2f1539255664bb50d772e SHA-1: ba84e9bed1005a9b4e6429a42d1c736a2719946e SHA-256: d64b5395abe1d3f3da28aec9f4f8ac3c27b36a694d2726946cd1cb06f1a5a9ac
382 Risk Score

Malware Insights

Rtf.Dropper.Agent-9965975-1 · confidence 95%

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1027 Obfuscated Files or Information T1105 Ingress Tool Transfer

The RTF file contains multiple indicators of exploitation for CVE-2017-11882, including a split hex Equation Editor ProgID and OLE object activation via \objupdate. The presence of a PE header within the hex-encoded OLE object data, coupled with ClamAV detection as Rtf.Dropper.Agent-9965975-1, strongly suggests that this file is a dropper designed to download and execute a second-stage payload.

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 ~1967KB 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_off0000129e.bin
742d0d6716bce63c7426f169b3042bfa9e432a0a5690cc02cb03b2ea0eb6cf63
rtf-objdata-decoded RTF \objdata at offset 0x129E 996500 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.
objdata_01_off001f2dd0.bin
a2124a25b651c0ac4f1b03472e0b5f0f351a1ff2bdd6230b727bd3863ad79f3d
rtf-objdata-decoded RTF \objdata at offset 0x1F2DD0 187261 bytes