Malicious PDF — malware analysis report

Static analysis result for SHA-256 af5137efb6d8713d…

MALICIOUS

PDF

69.1 KB Created: 2021-09-02 17:50:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 1157706008e30e0831b4b78e5a43d205 SHA-1: 3cddf9de9ff2f76ee4e4ad1490ba8eaebf90e607 SHA-256: af5137efb6d8713d7b39acab6732b49f6e52e472c524e27f5e27b895b6c018eb
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample is a PDF document identified as malicious by an ML classifier. It contains numerous external URIs and is structured as a link farm, with many links pointing to compromised WordPress sites or disposable hosting. The document body is heavily obfuscated and unreadable, suggesting it's not intended for direct user interaction but rather to facilitate traffic redirection or host further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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 https://huntic.ru/uplcv?utm_term=creatinina+baixa+pdf PDF link annotation
    • https://xn--hjrnskadeakademien-mtb.se/userfiles/file/zaxabigutezed.pdfIn PDF document text
    • https://nordiskvillaventilation.dk/userfiles/file/guvivagaj.pdfIn PDF document text
    • http://xahscw.com/userfiles/file/janezewum.pdfIn PDF document text
    • http://www.frank-diagn.hu/userfiles/files/waxim.pdfIn PDF document text
    • http://www.airportlimofortlauderdale.net/wp-content/plugins/formcraft/file-upload/server/content/files/160baed565d2f1---wajegonugox.pdfIn PDF document text
    • http://www.cheapmotorcycleinsurancepa.com/wp-content/plugins/super-forms/uploads/php/files/7ccd6tjh9lf0fl7i9jttr7ogu4/9464832233.pdfIn PDF document text
    • https://laihouston.com/wp-content/plugins/super-forms/uploads/php/files/588f8512d8e510f3bd0b1263d4145fd7/30778649155.pdfIn PDF document text
    • http://abwrosedale.com/uploads/files/59409636376.pdfIn PDF document text
    • https://expeditions-travel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075959f75583---tovenijanagomeroxajanod.pdfIn PDF document text
    • https://bienenaktuell.com/sites/bienenaktuell.com/files/file/wugewexonisi.pdfIn PDF document text
    • http://dvif.fr/userfiles/file/33955274576.pdfIn PDF document text
    • http://4998horo.gmmwireless.com/contents/files/likapalijibepisupud.pdfIn PDF document text
    • http://www.northeastmarquees.com/wp-content/plugins/super-forms/uploads/php/files/02e48f2722711995d9e2d283f30680ab/80295010871.pdfIn PDF document text
    • http://ukonlinedirect.com/userfiles/files/tufabixor.pdfIn PDF document text
    • http://cerrutistudio.eu/userfiles/files/tijilerewomaxezanelupusi.pdfIn PDF document text
    • https://studio45.live/wp-content/plugins/super-forms/uploads/php/files/3b4qb21oa6mlu3uui3pfnfa27s/bexobunefib.pdfIn PDF document text
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160719d2c990ab---diwurojiruwexo.pdfIn PDF document text
    • https://grdr.org/paidel/ckfinder/userfiles/files/dumukitu.pdfIn PDF document text
    • https://nikoljski.com/ckfinder/userfiles/files/77240580181.pdfIn PDF document text
    • http://dfanchem.com/upload/files/babowijeduj.pdfIn PDF document text
    • https://asiaviews.org/wp-content/plugins/super-forms/uploads/php/files/7g782a801p93l9pcdakghm6ll2/1210539263.pdfIn PDF document text
    • https://www.mybizwebsites.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bbe5fd5d4a4---15973810698.pdfIn PDF document text
    • https://svetpoznaniyaonline.ru/wp-content/plugins/super-forms/uploads/php/files/58476286d2d55d002682c6901009a7c2/45286174030.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_off0000b15f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB15F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c976.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC976 10432 bytes
SHA-256: 957915aee2f399727d06224b63040301f469ac1bede754a70e9a86d2c1bc83c9
font_02_sfnt_off0000e102.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE102 15220 bytes
SHA-256: b7d48aa1f0d1a1751b738f9f184bf1c243085de3a3ebfefb89d5672d69414b1c