Malicious PDF — malware analysis report

Static analysis result for SHA-256 51c40b5036b51c86…

MALICIOUS

PDF

114.8 KB Created: 2021-04-01 00:41:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-10
MD5: 9c8e5ef8c835538e38bc5246e84ac1c5 SHA-1: 3610c994a0748e58e52fa35a5e5c2f33896dfb26 SHA-256: 51c40b5036b51c866c8afaa5072018b51d233bcbda0dc88afe05101bbeac36b3
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains a large number of external links, many of which point to disposable hosting, indicating a link farm or SEO spamming operation. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and heuristic firings point towards a malicious document designed to redirect users to potentially harmful websites.

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://kuzutuzo.ru/award?keyword=libro+aula+espa%25C3%25B1ol+para+extranjeros+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4454049/normal_602aae1f2125e.pdfIn PDF document text
    • http://zujewubowufonug.scienceontheweb.net/bosch_automotive_electrics_and_automotive_electronics_systems.pdfIn PDF document text
    • https://kumaradogutaf.weebly.com/uploads/1/3/0/7/130775833/5286980.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4375357/normal_6029cd8935fe4.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413108/normal_604e124710693.pdfIn PDF document text
    • https://cdn.sqhk.co/jakofawesavo/nM3a66o/blank_newspaper_article_template.pdfIn PDF document text
    • http://xijivedijimidip.mygamesonline.org/samanibowazufofobajuka.pdfIn PDF document text
    • https://cdn.sqhk.co/zativojor/cLCkthd/puximuragafaxaba.pdfIn PDF document text
    • https://futisukafasuku.weebly.com/uploads/1/3/5/3/135345320/zipapifijazewoloze.pdfIn PDF document text
    • https://suxamoka.weebly.com/uploads/1/3/4/8/134876373/828d77a0441ef73.pdfIn PDF document text
    • http://bamiluzigu.mygamesonline.org/python_para_anlise_de_dados_portugus.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4446924/normal_5ff452f1d1740.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/17b8da5b-cb53-4bb8-a8b8-6bd712dcaaf9/armor_of_god_bible_study.pdfIn PDF document text
    • https://2a26c5f8-c4f8-4af8-830b-7e2c9961bd8e.filesusr.com/ugd/2e4362_fea5d4d3635a4888a2b8f92fe1ec6158.pdf?index=trueIn PDF document text
    • https://ffcd7f67-9b43-45c2-8e44-b15cca9583b8.filesusr.com/ugd/48bf55_41f1faa8f78f46c28ff5767c84a736d5.pdf?index=trueIn PDF document text
    • https://27dd58ca-3bab-4825-b0a2-cb75a9f796de.filesusr.com/ugd/aba4c5_c407312eb87749ca8969cc2682f7cf16.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/78af456b-cde2-4b5f-8efb-04fc5a145986/ruwojexumivexe.pdfIn PDF document text
    • https://091a8774-b5bd-4fb7-8799-8d1ca0ca44ad.filesusr.com/ugd/8716ab_a2f8a6de41894c4eab7e2274086af72b.pdf?index=trueIn PDF document text
    • https://2d130471-2a64-48ba-87cf-8f1e86c6acad.filesusr.com/ugd/9c43ec_1f2f94ce46ae41858fa4e15a61e2ef9d.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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00016874.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16874 5472 bytes
SHA-256: 058117967de15cca4d768bc8cf55e1948ba95a1e5abd8f2f2acc0d4d445eaf41
font_01_sfnt_off00017adf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x17ADF 13736 bytes
SHA-256: b84ac91007bef67a0193e340f8966a8231f6e834b9b47aff0b4502cce4b1a630
font_02_sfnt_off0001a606.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1A606 16068 bytes
SHA-256: e7273338525a866f49bd556f13a0e46ce1e8513f85f175d9d987aa1f8b89adb9