Malicious RTF — malware analysis report

Static analysis result for SHA-256 4123a19cda491f4d…

MALICIOUS

RTF

1.31 MB Created: 2018-03-05 23:33:00
MD5: 8ab70d92ff48ef6af9ab17bddc2aa512 SHA-1: 2b128c2a124e175649426ab305ad4a52015a2695 SHA-256: 4123a19cda491f4d31a855e932b8b7afdcf3faf5b448f892da624c768205a289
562 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.001 Malicious Link: Malicious Link T1059.001 Command and Scripting Interpreter: PowerShell T1059 Command and Scripting Interpreter

This RTF document exploits known vulnerabilities in the Microsoft Equation Editor (CVE-2017-11882 and CVE-2018-0798) to execute arbitrary code. The presence of hex-encoded PE headers and OLE object data strongly suggests the embedded payload is a dropper designed to download and execute further malicious content. The document body, a survey about job satisfaction and company ethics, is likely a lure to disguise the malicious intent.

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-6865126-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-6865126-0
  • \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.

FilenameKindSourceSize
objdata_00_off00010ff7.bin
0b457fbec85127a1e5beed7fe0ba4a09aa3103c31dd82936af9bb32d3620d253
rtf-objdata-decoded RTF \objdata at offset 0x10FF7 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_off000f762a.bin
07a8411898940a129fb32ea07971c5483a0118ee7d12fe1f3d57f103b544aafb
rtf-objdata-decoded RTF \objdata at offset 0xF762A 11845 bytes
objdata_02_off000f7652.bin
d0771b17e6418e479f528fc4aa124822669975a78f8dc3e35cdc4b0f7c212c4e
rtf-objdata-decoded RTF \objdata at offset 0xF7652 35 bytes
objdata_03_off000fd433.bin
46440b7979b22e1f7150802e7d3f6bbe10113c1dae213e566ba5e45d58e7da09
rtf-objdata-decoded RTF \objdata at offset 0xFD433 167011 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.65, consistent with packed or encrypted content.