Malicious PDF — malware analysis report

Static analysis result for SHA-256 78fc58fc704981c1…

MALICIOUS

PDF

84.4 KB Created: 2021-03-24 01:48:50 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 947bf8b531ed42452b073e83a3c939fb SHA-1: 0ea637075987f240ff9cffed7b8c56ff01f6b2b3 SHA-256: 78fc58fc704981c1590bb24a103ce0fd801daa881e4c03b3474faa5ad51d3f8d
186 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics indicate the presence of a large link farm pointing to external PDFs hosted on disposable domains, suggesting a tactic for SEO manipulation or payload distribution. While no scripts were extracted, the structure and heuristic firings strongly suggest an attempt to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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 https://cdn-cms.f-static.net/uploads/4497109/normal_5fda38a613c8f.pdf In PDF document text
    • https://cdn-cms.f-static.net/uploads/4402960/normal_5fd222f638dfd.pdfIn PDF document text
    • https://cdn.sqhk.co/dajebala/WJvy53k/shake_shack_order_wrong.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4485579/normal_5ff935a15e514.pdfIn PDF document text
    • https://cdn.sqhk.co/lobinazema/Qijcg0f/bridge_constructor_playground_mod_apk_2._0.pdfIn PDF document text
    • https://cdn.sqhk.co/zowesifona/fhididg/52562032921.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/wb/ENAH/~3/0IJhScypsXo/wb?keyword=funcion%20del%20sistema%20endocrino%20para%20ni%C3%B1osPDF link annotation
    • https://467375c7-a7a6-4806-a9b7-892c2a528f89.filesusr.com/ugd/911174_188a4b9e443a485eb550f98e041037f7.pdf?index=trueIn PDF document text
    • https://07f52280-50dc-49c2-beec-a2e30bf849d0.filesusr.com/ugd/7b8f90_4a96ba5bdce14efbb92e86a96609cae6.pdf?index=trueIn PDF document text
    • http://sezaluri.rf.gd/finoru.pdfIn PDF document text
    • http://fasilew.epizy.com/xufebef.pdfIn PDF document text
    • https://s3.amazonaws.com/tikoweravisixu/7644292331.pdfIn PDF document text
    • https://s3.amazonaws.com/dogevazapiwediw/classroom_assessment_what_teachers_need_to_know_6th_edition.pdfIn PDF document text
    • http://burupopevetu.rf.gd/phonetic_alphabet_english_pronunciation.pdfIn PDF document text
    • http://pojurevowope.epizy.com/vugazilurem.pdfIn PDF document text
    • https://e924225a-aa46-4bfc-8e56-7341551e1833.filesusr.com/ugd/54dfea_fe4d818c064b42cf8d3431289a8f5d60.pdf?index=trueIn PDF document text
    • https://6e229dea-1f83-4be8-8cd3-388eabd4f5e3.filesusr.com/ugd/1cfe37_3688925fe56c415ea777f3cbdc8b97bd.pdf?index=trueIn PDF document text
    • https://20996a60-9695-4f45-8fdb-44bdc783da55.filesusr.com/ugd/c57cae_b586d05d3e7840d09a66159412ff2a9b.pdf?index=trueIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010a1c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A1C 5384 bytes
SHA-256: e641cc0d8f8dd22da8584f16d4b8452a95e10b58ff2d4df5eab552c298fa47f9
font_01_sfnt_off00011c12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C12 11700 bytes
SHA-256: fd07919b8b34765710f15edd5ff4470d76ab2fbf1853b63526f07cdab17d31e2

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