Rtf.Dropper.Agent-8723498-0 — RTF malware analysis

Static analysis result for SHA-256 87621ec7df1d508b…

MALICIOUS

RTF

18.7 KB First seen: 2020-09-15
MD5: f1b6efc051cec7c98d6e07625c6dd29a SHA-1: 1a090ce40374e34a181920d04c7107ff0bbfdc2a SHA-256: 87621ec7df1d508baccdb7058a289f3da0c7ec03b9bfc4321658b1f1b837264c
240 Risk Score

Malware Insights

Rtf.Dropper.Agent-8723498-0 · confidence 95%

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains an embedded OLE object that exploits CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. This exploit is designed to execute arbitrary code, likely to download and run a secondary payload. The ClamAV detection name 'Rtf.Dropper.Agent-8723498-0' further supports its classification as a dropper.

Heuristics 6

  • Split hex Equation Editor ProgID + OLE object critical CVE likely 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.
  • 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.
  • ClamAV: Rtf.Dropper.Agent-8723498-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-8723498-0
  • \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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001679.bin rtf-objdata-decoded RTF \objdata at offset 0x1679 1611 bytes
SHA-256: ad94f424e5cb9d00d783295f45cb133958f8b065628872413466e98afaa2f042

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