Malicious PDF — malware analysis report

Static analysis result for SHA-256 b51d972787fa29a5…

MALICIOUS

PDF

81.8 KB Created: 2021-09-19 23:49:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: acdd3f3ca2b1fd45b3d8df5eeda45450 SHA-1: 793b24b545f2227ae582117c7de0301e1d22a703 SHA-256: b51d972787fa29a5e89046335a81f56f91e8e630352733a21734c03dd33c55d3
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains a high number of external links, many pointing to compromised WordPress sites or disposable hosting, indicating a likely phishing or malicious redirection attempt. The ClamAV detection and ML classifier strongly suggest malicious intent, likely to lure users to malicious content or download further payloads. No scripts were extracted from this sample, but the extensive link farm is sufficient evidence of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://medvor.ru/uplcv?utm_term=minna+no+nihongo+fukushuu+f+answers PDF link annotation
    • https://ashleymongolia.mn/uploads/files/82463020128.pdfIn PDF document text
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d35230fb96---niwuzenejutakusitozozibub.pdfIn PDF document text
    • https://peisheng.org/uploads/ckfiles/files/613fcb0b065e0.pdfIn PDF document text
    • https://grandplaza.bg/uploads/assets/file/83084002849.pdfIn PDF document text
    • https://nordavril.com/userfiles/file/zawugazawokodobokawivalug.pdfIn PDF document text
    • http://sevenseahotel.com/uploads/images/files/norufu.pdfIn PDF document text
    • https://mikepromedia.com/wp-content/plugins/super-forms/uploads/php/files/9e8c751266bc8a9a379579f741166346/18310334775.pdfIn PDF document text
    • http://ros.by/ckfinder/userfiles/files/xujufavubarofawududibu.pdfIn PDF document text
    • http://english-island.pl/wp-content/plugins/super-forms/uploads/php/files/jclapqhqd2dad4e1ab031mrt61/48527885103.pdfIn PDF document text
    • http://kxxbs.com/uploadfiles/file/a/kumubepoxidemefufufeguzo.pdfIn PDF document text
    • http://aiaato.com/FileData/ckfinder/files/20210917_FC57D3A264BE1E4E.pdfIn PDF document text
    • http://hkwwta.org/userfiles/kalox.pdfIn PDF document text
    • https://stewsites.com/wp-content/plugins/super-forms/uploads/php/files/b6eb4c6821181518ce132ebe8c4a9372/wuleseremusarinugataxurob.pdfIn PDF document text
    • https://buonoantonio.it/userfiles/file/11586319892.pdfIn PDF document text
    • http://dakov.hu/_user/file/1226578594.pdfIn PDF document text
    • https://leanuslab.com/UserFiles/file/15913105344.pdfIn PDF document text
    • https://homeuu.biz/upload/ckeditor/pages/files/sidazenidupepebirevofego.pdfIn PDF document text
    • http://stensoproject.com/userfiles/files/nigukuwejejiwera.pdfIn PDF document text
    • https://aarhuskortet.dk/images/file/vevupu.pdfIn PDF document text
    • http://epplast.com/files/file/85234574321.pdfIn PDF document text
    • http://nenkin-t.com/upload_img/ck/files/92595455286.pdfIn PDF document text
    • https://supermovi.com/userfiles/files/57247318981.pdfIn PDF document text
    • http://zs-oilfieldequip.ru/d/files/88749824947.pdfIn PDF document text
    • http://wlpp.net/images/blog/file/roredidezotilakidujo.pdfIn PDF document text
    • http://lucidarepavimentimarmogenovaealessandria.it/userfiles/files/xaxeranusis.pdfIn PDF document text
    • http://shqinze.net/admin/upimg/file///dinumeparob.pdfIn 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://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_off0000d37c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD37C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000eb93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB93 10620 bytes
SHA-256: dcd43f7a39d658526c4c86bc2691deffc68c5185848b1d855853c3e5cafab049
font_02_sfnt_off000103e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103E4 20460 bytes
SHA-256: a063434ff0c0c733e20c7945d5f8e587a32731a827569c52b7af771b55463553

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