Malicious RTF — malware analysis report

Static analysis result for SHA-256 d0ebb857a85b54d5…

MALICIOUS

RTF

2.61 MB First seen: 2022-05-31
MD5: 914b7d3fb6bac926af66c20bb11c7ec5 SHA-1: ef32f61d184ebe2ae29a1d55cfee1af2f1876ed0 SHA-256: d0ebb857a85b54d585e981323a57a10c8ab800f082656299e717854b3da0ff65
340 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.001 PowerShell

The RTF file contains embedded OLE objects and triggers the CVE-2017-11882 vulnerability through the Equation Editor. This exploit is designed to execute a payload, indicated by the presence of a PE header in hex data and the ClamAV detection as Rtf.Dropper.Agent-9965975-1. The embedded data suggests an attempt to execute 'Client.exe' from 'C:\Path\Client.exe'.

Heuristics 8

  • 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.
  • 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_off000012ab.bin
7dbd99011f245e69eba888b188ee9806ee8c1bd5a996c5dd400f4f26dd5844a0		 rtf-objdata-decoded RTF \objdata at offset 0x12AB 369451 bytes
objdata_01_off000c1270.bin
c15a908dd43ec603b552f3652117fbcce46d419a9a10490458118a5a4409d1b8		 rtf-objdata-decoded RTF \objdata at offset 0xC1270 462749 bytes

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