Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8f4c604012fdc39…

MALICIOUS

PDF

88.0 KB Created: 2021-07-22 00:16:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 25966ac38dc297d52a18b53efaf19a99 SHA-1: b6c2d0d6e6ded986cce4029433b39ee5f2b35e1b SHA-256: a8f4c604012fdc39c800a118a4968d52d93fc9376cec92a754729e573ac533a2
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document containing embedded JavaScript, which is a common technique for executing malicious code. The heuristics indicate the PDF acts as a link farm, with many URLs pointing to compromised WordPress upload directories, suggesting an attempt to host or distribute further malicious content. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 6

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://www.digitalsofts.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c573a5c2a71---4429627233.pdf In PDF document text
    • http://jarauwerdaenzn.nl/userfiles/file/lajimis.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/16083b37dd74d7---sumelunezituruwitasamuxej.pdfIn PDF document text
    • http://beetsom.com/PROGRAM_FCKeditor_UserFiles/file/61073467860f5d301de2b9.pdfIn PDF document text
    • https://socialchangefactory.org/wp-content/plugins/super-forms/uploads/php/files/0f5db7766f05541c07b0f1fa97d937bd/fowapumanoxab.pdfIn PDF document text
    • http://thebrownsfamilyreunion2008.com/clients/81208/File/63432834659.pdfIn PDF document text
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/luv17bvfif0c00guf2n2on4c76/mirumakuveloluzapa.pdfIn PDF document text
    • https://aslimitada.com/userfiles/file/bulapuzejekejawotemuzezo.pdfIn PDF document text
    • http://szsahsh.com/uploads/files/papigos.pdfIn PDF document text
    • http://gzky.cn/dubeite/ckfinder/userfiles/files/20210614_200052.pdfIn PDF document text
    • http://pphjako.pl/userfiles/file/daripesobiwidigozorosurup.pdfIn PDF document text
    • https://coloreverything.love/wp-content/plugins/super-forms/uploads/php/files/cc5dc22839000534720f1de4eb93e27d/42007716200.pdfIn PDF document text
    • http://battlegrouponline.com/app/webroot/js/ckfinder/userfiles/files/gikiri.pdfIn PDF document text
    • http://mijneigenlift.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a59b6dee1a2---wabagivoboxenolozuvan.pdfIn PDF document text
    • http://coimbra.hu/uploads/ckfinder/userfiles/files/feribunaxow.pdfIn PDF document text
    • https://ceccarbotosani.ro/userfiles/file/dunatilegafoxakotaf.pdfIn PDF document text
    • http://anhbanglaw.com/userfiles/file/xometajosuvosim.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a9921705da4---37648152057.pdfIn PDF document text
    • http://nfraccon.org/userfiles/file/webimasug.pdfIn PDF document text
    • https://alsterparkett.de/wp-content/plugins/super-forms/uploads/php/files/jq049p9g87srs3c9fbbit2k6mv/juvepovu.pdfIn PDF document text
    • http://mirrorgallery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a3bd6da9bc---2214428690.pdfIn PDF document text
    • https://angkoronetour.com/userfiles/file/rujaji.pdfIn PDF document text
    • https://suhrsmad.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16079e9d3eabf3---domiganenakezogodi.pdfIn PDF document text
    • http://altiro.nl/home/tjerk/file/xolufebanijatemaroz.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=thalia+and+tommyPDF 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_off0000f1cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1CF 10188 bytes
SHA-256: 4838a92158e33bdcc32bbdfb24611e96004ffb8ada87fe0b85b4efec20cf0a21
font_01_sfnt_off00010864.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10864 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012076.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12076 19040 bytes
SHA-256: 2b0f5b26a3998f41079e054e9fa2c4dadb72e6c4c6135b1d428fbc5f4c6c0185

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