Malicious PDF — malware analysis report

Static analysis result for SHA-256 1631a91629014362…

MALICIOUS

PDF

115.3 KB Created: 2021-07-01 21:26:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 553cac9cb75850233ba04cd7f00e21bc SHA-1: 79d8eb15ccb1dbeec1bdccc445208788c1899a51 SHA-256: 1631a91629014362a1c9ed780d065f0fcf594ca282dc82db432f3ed84d63c70f
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains a large number of external links, many of which point to compromised WordPress sites. The ML classifier strongly indicated maliciousness, and the heuristic firings suggest this is a link farm designed to distribute traffic to potentially malicious or SEO-manipulated content. No scripts were extracted, but the structure and URL patterns are indicative of a malicious document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://stroynerud-sm.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160adb381e3438---guvigujajimejeda.pdf In PDF document text
    • http://www.jesuseslaroca.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607d3d1530ffb---samowuwutelivesexinetef.pdfIn PDF document text
    • https://avigailpekelman.com/sites/default/files/file/55975958191.pdfIn PDF document text
    • https://medok18.ru/wp-content/plugins/super-forms/uploads/php/files/210c2cc7945e4be82599b39526695c66/bewekelix.pdfIn PDF document text
    • https://vydavatelstvoklett.sk/userfiles/file/41450172985.pdfIn PDF document text
    • http://dianacb.cz/userfiles/file/82330803876.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160923f2f23ea2---memeriwegunotabojunidefez.pdfIn PDF document text
    • http://stacjaregeneracja.pl/userfiles/file/zolepogijila.pdfIn PDF document text
    • http://ckrestaurantgroup.com/ckfinder/userfiles/files/72666824539.pdfIn PDF document text
    • https://aquafilling.com/userfiles/file/27541532590.pdfIn PDF document text
    • http://www.alquilerbares.com.ar/wp-content/plugins/formcraft/file-upload/server/content/files/1606d301cc9497---jibomitero.pdfIn PDF document text
    • http://weberstellen.ch/userfiles/file/77366024944.pdfIn PDF document text
    • http://polskienarty.pl/data/aktualnosci_imgs/file/xegamipuba.pdfIn PDF document text
    • http://zdravi-kromeriz.cz/files/file/64430249179.pdfIn PDF document text
    • http://skolicka.eu/foto/images/file/rejunufulatinoro.pdfIn PDF document text
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/1609dc780472c9---puzevatomulogulapesabov.pdfIn PDF document text
    • https://www.simcoerecovery.net/wp-content/plugins/super-forms/uploads/php/files/kb6vnvok8r3pfcs4jnkb5mrlpo/nozebujaginulinijowusawed.pdfIn PDF document text
    • https://www.chauffeur-prive-nice.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16077238a25edf---sebikirezef.pdfIn PDF document text
    • https://www.mixedclass.com.au/wp-content/plugins/super-forms/uploads/php/files/l2lf3ea5bgkveg05uif6h99l05/wasokamu.pdfIn PDF document text
    • http://mognational.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a0549b62069---88763662958.pdfIn PDF document text
    • http://mognational.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090b26553970---87569095789.pdfIn PDF document text
    • https://livingcircles.ch/wp-content/plugins/formcraft/file-upload/server/content/files/16083c7e8ed2de---39516755021.pdfIn PDF document text
    • https://hogies.com/includes/template/uploads/file/jekiwuwomefopizekuxepomo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=book+13+test+3+reading+answerPDF 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_off00015f28.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15F28 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001773a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1773A 17844 bytes
SHA-256: de41f9a28ceddf5c1ccb9ce4bda07b31c9f373000aed621689e77d657c322cc5
font_02_sfnt_off0001a54d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1A54D 10832 bytes
SHA-256: 2e42bcdbceeee73addfeb0639f555ab19d37b5586e2c121e59a5beecb8426e64

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