Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b2ee08aeb54de3…

MALICIOUS

PDF

90.2 KB Created: 2021-09-03 03:13:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: d681fd8fc95921f36c5544c64d0b4734 SHA-1: 6d9e1e3df041313c15379a7797257f1a5f04ec5e SHA-256: 81b2ee08aeb54de30e91c89e4a980ccc2720a6021c36cb9314e405ae42e1fbd1
156 Risk Score

Malware Insights

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

The PDF file contains numerous links to external websites, many of which are hosted on compromised or disposable domains, indicating a link farm designed to redirect users. The presence of a ClamAV detection for 'Pdf.Phishing.Trojan' and ML classifier flagging further supports its malicious nature. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://computerdoki.hu/user/file/bugexinekokurimotu.pdf In PDF document text
    • http://watthaistuttgart.de/userfiles/file/50995415094.pdfIn PDF document text
    • http://mosjob.ru/images/file/60443210535.pdfIn PDF document text
    • http://wsp.pl/userfiles/file/sisokafekewujokulikogivi.pdfIn PDF document text
    • http://www.majoriscambio.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ff0d641392e---pimebakupasawafosu.pdfIn PDF document text
    • https://phuquiland.com/upload/files/72487124941.pdfIn PDF document text
    • http://domainecomps.com/documents/files/61231081634.pdfIn PDF document text
    • http://enidental.com/userfiles/file/20210803174254.pdfIn PDF document text
    • https://noble-worldwide.com/wp-content/plugins/super-forms/uploads/php/files/24179515d2a3a88126b414773e7929df/zugitidijujidupekuwezo.pdfIn PDF document text
    • http://stihoplet.by/upload/editor/files/pilulegelaviwolasoj.pdfIn PDF document text
    • http://bukharasuwanee.com/sites/default/files/file/vikowedadoxijutefupetotul.pdfIn PDF document text
    • http://olsztyntransportmedyczny.pl/userfiles/file/jogetigibosaviwese.pdfIn PDF document text
    • https://guapa2.com/admin/fck/file/53521988876.pdfIn PDF document text
    • https://polinagerz.ru/wp-content/plugins/super-forms/uploads/php/files/7uou7og2gt5h9r3b5i6behskjk/11962768627.pdfIn PDF document text
    • http://www.pattyn360.com/upload/forum/files/puvetuzoxenewugasog.pdfIn PDF document text
    • http://traditionsradio.com/wp-content/plugins/super-forms/uploads/php/files/s16ti24pidj0bk4ptr6tu4ps61/88207016816.pdfIn PDF document text
    • http://www.zav-mito.si/wp-content/plugins/formcraft/file-upload/server/content/files/1607cdcda308d7---56985580064.pdfIn PDF document text
    • http://kulturazebrak.cz/userfiles/27378651173.pdfIn PDF document text
    • https://www.marbelitesa.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1606d9ff8c44bc---tufotanuxenirosar.pdfIn PDF document text
    • https://messianic.live/wp-content/plugins/super-forms/uploads/php/files/7121aed028ec834038f154c85ad31173/sepanuxejujipuzezaja.pdfIn PDF document text
    • https://www.hinkler.com.au/application/third_party/ckfinder/userfiles/files/gaxugonetuwig.pdfIn PDF document text
    • https://lostsoulsmemorialnj.org/wp-content/plugins/super-forms/uploads/php/files/3d9f37df250d862f037ca982b602b237/nunujevomim.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=age+discrimination+definition+pdfPDF 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_off0000fdab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDAB 10896 bytes
SHA-256: 99f6d93c4daa7d718e0adfa854de15377fcd06655521c7efa6ac8b640e07b571
font_01_sfnt_off000116aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x116AA 17240 bytes
SHA-256: 5debe79ce15ef3d10d3abffedcc70a89700b66b8aacdacdbeb4ddb1e98f92ecf
font_02_sfnt_off00014306.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14306 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1