Malicious RTF — malware analysis report

Static analysis result for SHA-256 3e04eb55095ad6a4…

MALICIOUS

RTF

284.3 KB Created: 2019-02-21 05:54:00
MD5: 6930bd66a11e30dee1ef4f57287b1318 SHA-1: ddee9282bab537136f563f3c93856e5793ab9e5a SHA-256: 3e04eb55095ad6a45905564d91f2ab6500e07afcdf9d6c710d6166d4eef28185
400 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains multiple critical heuristic firings indicating exploitation of Equation Editor vulnerabilities, specifically CVE-2017-11882 and CVE-2018-0798. It also shows evidence of OLE object activation and MSXML SAX exploitation (CVE-2017-8759). These indicate the file is designed to execute arbitrary code via these exploits, likely to download and run a secondary payload. No specific family could be identified.

Heuristics 10

  • CVE-2018-0798 — Equation Editor Matrix record overflow critical CVE exact CVE_2018_0798
    RTF contains hex-encoded MTEF Matrix record exploit signature (NOP-sled 0x60 + padding 0x61 + return address 0x0BFB). CVE-2018-0798 exploits a stack buffer overflow in EQNEDT32.EXE's Matrix record parser and affected Equation Editor broadly, including builds patched for CVE-2017-11882. Widely used by APT groups (Conimes, KeyBoy, Emissary Panda, Rancor).
  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • 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.
  • Equation Editor CLSID critical RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • ClamAV: Rtf.Dropper.Agent-6894863-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-6894863-0
  • \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.
  • Package object class high RTF_OBJCLASS_PACKAGE
    OLE Package object — can wrap arbitrary files
  • OLE object data medium RTF_OBJDATA
    RTF contains 3 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2003/wordml

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00010670.bin
05d331457cf792172c29647da4b74c4415e192c9acdd929c2f37e3249e649777		 rtf-objdata-decoded RTF \objdata at offset 0x10670 97394 bytes
objdata_01_off0004134b.bin
86cf1ec1c75e7924c914750be9a65ab9e0117cdbb6602610e93dd91f0ad6192c		 rtf-objdata-decoded RTF \objdata at offset 0x4134B 11845 bytes
objdata_02_off00041373.bin
d0771b17e6418e479f528fc4aa124822669975a78f8dc3e35cdc4b0f7c212c4e		 rtf-objdata-decoded RTF \objdata at offset 0x41373 35 bytes

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