Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4e8d6b320d2ada1…

MALICIOUS

PDF

83.2 KB Created: 2021-06-30 20:05:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 6251c31d6c5c09d2cd3175ee5006c40d SHA-1: 84e222af5362b8ff667f7149dea436d55f01f451 SHA-256: b4e8d6b320d2ada1f966e89c5fcbb751aa832e7ee533964562db754a1526dab4
96 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to compromised WordPress sites. The ML classifier strongly indicated maliciousness, and the heuristic firings confirm the presence of a link farm hosted on potentially compromised infrastructure. The document body is heavily obfuscated and unreadable, suggesting it is not intended for human consumption but rather to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://www.nanodrywash.com/wp-content/plugins/formcraft/file-upload/server/content/files/160986f18298a7---57791652746.pdf In PDF document text
    • https://autosaloncenter.com/uploads/file/68830157786.pdfIn PDF document text
    • http://xn----7sbabaajmdfbk3ddf3azka3b6a2r.xn--p1ai/ckfinder/userfiles/files/serodi.pdfIn PDF document text
    • http://www.melodypods.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a74fe6ce22d---jirisizezivo.pdfIn PDF document text
    • https://aplusadvance.com/naver_editor/data/file/majivezetun.pdfIn PDF document text
    • https://3dreamstudios.com/wp-content/plugins/super-forms/uploads/php/files/e335617e0f2f9447c56124ab2ab2ee11/viwopeguwebapiwopadadazu.pdfIn PDF document text
    • http://lawngo.net/fckfiles/venejagosa.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d6906e42ae---95465592588.pdfIn PDF document text
    • https://brusroom.com/wp-content/plugins/super-forms/uploads/php/files/716203e65d3964ca0feb82704daf1844/10593895774.pdfIn PDF document text
    • https://best-turbos.com/wp-content/plugins/super-forms/uploads/php/files/440e57c1a213b42bc2b5d9429098a0bc/zipajivajuwodetaxapo.pdfIn PDF document text
    • https://arizonalightingsales.com/wp-content/plugins/super-forms/uploads/php/files/9ed4c6efa835c804014c7b53e3a38e46/konepajaxovere.pdfIn PDF document text
    • https://diaochue.vn/userfiles/file/12398213191.pdfIn PDF document text
    • https://mattress-leader.com/media/28430423985.pdfIn PDF document text
    • https://designcoordinators.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f787c4a7b3---95634355201.pdfIn PDF document text
    • http://feriaalainversa.com/uploaded/files/53474967026.pdfIn PDF document text
    • http://arohitourandtravels.com/userfiles/file/38533434950.pdfIn PDF document text
    • https://xn--78-6kce7dfhb9dwb.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/9162f0186b67c31b5220a2c6e1ccdc37/pomutusefak.pdfIn PDF document text
    • https://kede.org/userfiles/file/68188019142.pdfIn PDF document text
    • http://littlepearlspublishing.in/data/eimages/file/63851980506.pdfIn PDF document text
    • http://www.sensible-seeds-premium.com/wp-content/plugins/formcraft/file-upload/server/content/files/16092b48ae4b20---41137823331.pdfIn PDF document text
    • http://wangyiphk.com/userfiles/beramalatuwanubaba.pdfIn PDF document text
    • http://coyada.com/up_images/up_images/disegi.pdfIn PDF document text
    • http://mountmedpharmacy.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160dc231d55c55---25617151781.pdfIn PDF document text
    • http://cathugo.de/res/wysiwyg/file/wibiv.pdfIn PDF document text
    • https://k2salight.com/wp-content/plugins/super-forms/uploads/php/files/412bfd0206370a3bc67c5566f1ef22ed/xopenuseru.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=good+grains+to+eatPDF 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_off0000e3f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3F6 10416 bytes
SHA-256: 9aab1b90fb2faac72d648a2f1b360835bede24fd8acf46c2bab115b087b1993c
font_01_sfnt_off0000fb7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB7E 17068 bytes
SHA-256: f8d66a0365a9ca587a624eacb799088a182630ca737a6f16edcff730ef626920
font_02_sfnt_off000127d1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x127D1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1