RTF malware analysis — malicious · 4fce3d38e0a30808

MALICIOUS

RTF

1.30 MB Created: 2019-02-21 22:28:00

MD5: b6eb15c9d9c10eb399ad9d0adcbdc0d0 SHA-1: ecdca0d0056bfd1a6a7269120e3f4104fc6aaa10 SHA-256: 4fce3d38e0a308088cd75c2ef1bb5aa312e83447d63a82f62839d3609a283b02

562 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution

The RTF document exploits known vulnerabilities in the Microsoft Equation Editor (CVE-2017-11882 and CVE-2018-0798) and MSXML (CVE-2017-8759) to execute arbitrary code. The presence of large hex-encoded data blocks and PE headers within OLE object data suggests the embedding of a malicious executable. The ClamAV detection further confirms its malicious nature as a dropper.

Heuristics 15

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.
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.
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
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-6865280-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Rtf.Dropper.Agent-6865280-0
\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
Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX

RTF contains ~1311KB of hex-encoded data inside \objdata sections — may hide a payload
OLE object data medium RTF_OBJDATA

RTF contains 4 \objdata section(s) — embedded OLE objects
Embedded OLE object medium RTF_OBJEMB

RTF contains \objemb — embedded OLE object
OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM

RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.
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.
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 4

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off0000e1f8.bin` `0b457fbec85127a1e5beed7fe0ba4a09aa3103c31dd82936af9bb32d3620d253`	rtf-objdata-decoded	RTF \objdata at offset 0xE1F8	471780 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.89, consistent with packed or encrypted content.
`objdata_01_off000f482e.bin` `07a8411898940a129fb32ea07971c5483a0118ee7d12fe1f3d57f103b544aafb`	rtf-objdata-decoded	RTF \objdata at offset 0xF482E	11845 bytes
`objdata_02_off000f4856.bin` `d0771b17e6418e479f528fc4aa124822669975a78f8dc3e35cdc4b0f7c212c4e`	rtf-objdata-decoded	RTF \objdata at offset 0xF4856	35 bytes
`objdata_03_off000fa63a.bin` `46440b7979b22e1f7150802e7d3f6bbe10113c1dae213e566ba5e45d58e7da09`	rtf-objdata-decoded	RTF \objdata at offset 0xFA63A	167011 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.65, consistent with packed or encrypted content.

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