Malicious PDF — malware analysis report

Static analysis result for SHA-256 4831d6d1e22161ae…

MALICIOUS

PDF

82.1 KB Created: 2021-09-05 19:43:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: d29a7ea2f8013729c40dd7c6a2fb2e37 SHA-1: 3fd0277410d2801e4847c2cc9160f60534850395 SHA-256: 4831d6d1e22161ae5e34884dc7a6d2e594617d8ca74959c0ce11145f5a7526c3
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a large number of embedded URLs, many of which point to compromised CMS upload storage or disposable hosting, indicating a link farm. The ML classifier strongly flagged this PDF as malicious. While no scripts were extracted, the primary function appears to be redirecting users to potentially malicious or SEO-manipulated content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 5

  • 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 http://grandp.ru/userfiles/file/kapavevak.pdf In PDF document text
    • https://baobihungphu.com/media/ftp/file/tuxoweja.pdfIn PDF document text
    • https://neoville.ru/wp-content/plugins/super-forms/uploads/php/files/df38a75af628677e7f0637860292145f/konewokedidepug.pdfIn PDF document text
    • http://socialbomjesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/160864926b32fb---16049673127.pdfIn PDF document text
    • http://hsaltsj.com/uploads/files/92857311509.pdfIn PDF document text
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c49f67e8adf---pupotosifixutogaxox.pdfIn PDF document text
    • https://dhesient.com/media/65298622589.pdfIn PDF document text
    • https://maintogelonline2.com/contents//files/13735453895.pdfIn PDF document text
    • http://extrastyle.ee/ckfinder/userfiles/files/77969098290.pdfIn PDF document text
    • http://prmakeup.com/Image/files/nukavojazenafalux.pdfIn PDF document text
    • http://barrarioservicos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607179f0b6901---xufalemijowanajonafasob.pdfIn PDF document text
    • http://www.shipsupply.co.mz/wp-content/plugins/formcraft/file-upload/server/content/files/16124f117d33b5---viguginozubig.pdfIn PDF document text
    • https://calldidocta.com/wp-content/plugins/super-forms/uploads/php/files/a38902020771cc9b8275df6a7aa36ac5/vukesokelomiwotipen.pdfIn PDF document text
    • http://dralituncer.net/userfiles/file/lanakevim.pdfIn PDF document text
    • https://wilsonbarrera.com/inicio/wp-content/plugins/formcraft/file-upload/server/content/files/160b927864fb75---96117855238.pdfIn PDF document text
    • https://www.chartsunlimited.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/1609b40a9f3f5e---wawiso.pdfIn PDF document text
    • https://quickonboarding.com/wp-content/plugins/super-forms/uploads/php/files/0f146767b7daae1a162bddde9953d564/66259929886.pdfIn PDF document text
    • https://www.scilights.com/wp-content/plugins/super-forms/uploads/php/files/f2db0b932c0609fc01db11303040b177/xusovi.pdfIn PDF document text
    • http://bizwd.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9916b985ab---ludarimofaremu.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fd2833f844---4402948201.pdfIn PDF document text
    • https://alfa-pechati.ru/wp-content/plugins/super-forms/uploads/php/files/45ef6ebf1c440e2d35794661f5b94010/29191676105.pdfIn PDF document text
    • https://kontiko.com/ktkweb3/images/upload/files/56799630225.pdfIn PDF document text
    • http://wsp.pl/userfiles/file/36084441289.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=business+process+management+pdf+downloadPDF link annotation
    • 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_off0000dcdd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCDD 16804 bytes
SHA-256: 08b848707fb53cded62a38beceec23ef2854866556497a671fe00c89f4ef5292
font_01_sfnt_off00010848.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10848 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001205f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1205F 11204 bytes
SHA-256: 871c2b46c16d44cc1f8d16651a34f374742afad33e47a78be19f93bd2bed8373

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