Malicious PDF — malware analysis report

Static analysis result for SHA-256 eb8d917a819e7572…

MALICIOUS

PDF

95.8 KB Created: 2021-09-05 11:21:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c50c0d44aaa888b8c35c0526169a9062 SHA-1: de08f39a92cbf08d4dd5b134abe970d80fa406ce SHA-256: eb8d917a819e757231d6f0133c4d49e8269b648fbe3c55d73b6aa045a3aed1d1
96 Risk Score

Malware Insights

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

The PDF file was identified as malicious by an ML classifier with high confidence. It contains numerous external URIs and links to compromised CMS upload directories, suggesting it's part of a link farm or SEO poisoning campaign. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but likely serving as a vessel for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9806

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://synerhu.ru/uplcv?utm_term=acculturation+meaning+pdf PDF link annotation
    • https://dacola.com/upload/files/mimojigefukuzejepet.pdfIn PDF document text
    • http://www.mvdisposal.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d87c2ac4790---lologizagolose.pdfIn PDF document text
    • http://www.mvdisposal.com/wp-content/plugins/formcraft/file-upload/server/content/files/160718828023f0---81897233433.pdfIn PDF document text
    • http://dinskayarealty.ru/media/file/jumunomun.pdfIn PDF document text
    • http://globaltruthmediagroup.com/clients/a/aa/aa8380eac451876ae6ab993bf3a720d6/File/gizizumazut.pdfIn PDF document text
    • https://esperanzadeavila.com/fotos/file/zepuwebunagenuvezig.pdfIn PDF document text
    • https://grandhotelbulgaria.com/userfiles/file/gobovevomubovujogake.pdfIn PDF document text
    • https://ooo-kenk.ru/userfiles/file/zasopu.pdfIn PDF document text
    • https://yar-net.ru/userfiles/file/64555805983.pdfIn PDF document text
    • https://bd-sokolovska.eu/userfiles/file/21061388779.pdfIn PDF document text
    • https://studiogreenwich.ru/wp-content/plugins/super-forms/uploads/php/files/f5123ea048caea0e6eedc3cc28fd2e76/37532887019.pdfIn PDF document text
    • http://www.ddd-iasi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1606cde5f2bfd4---jizifosagixopi.pdfIn PDF document text
    • http://ophtalmic-overnight.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1607834c60fb08---71022313760.pdfIn PDF document text
    • https://halobysciton.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083b411300d6---gorupanevogasenebepe.pdfIn PDF document text
    • https://outsourcedbackoffice.co.uk/wp-content/plugins/super-forms/uploads/php/files/fbf2710e0463578ccc0fa91c6f6f2d92/bovejakavu.pdfIn PDF document text
    • https://mindspacepsytherapy.com/upload/ckfinder_temp/files/20210530042448.pdfIn PDF document text
    • http://carriewoodfamily.com/clients/5/5b/5b9f2fb360c4065436fb7fe1267c3612/File/ropesinutemutapajivu.pdfIn PDF document text
    • http://ilovegabal.net/fckeditor/_upload/file/galiginedo.pdfIn PDF document text
    • http://bhs-class1957.com/clients/35434/File/81116717581.pdfIn PDF document text
    • https://3dreamvr.com/wp-content/plugins/super-forms/uploads/php/files/a53bcedbc875124268f8e1b1d5b39c0d/88374608974.pdfIn PDF document text
    • http://secohthailand.com/file_media/file_image/file/jowurowoponepukorozuko.pdfIn PDF document text
    • https://onlineadda.net/ckfinder/userfiles/files/12198304414.pdfIn PDF document text
    • https://www.mnspineandsport.com/wp-content/plugins/super-forms/uploads/php/files/11927f2d578ffe61508e3bbab65c9ef0/tufiwenitupu.pdfIn PDF document text
    • http://nbnjl.com/userfiles/files/11864599725.pdfIn PDF document text
    • https://icbacademy.com/upload/files/xamodevikedoku.pdfIn PDF document text
    • https://spbmworld.com/anaeter_capital/siteadmin/userfiles/files/kejifalijo.pdfIn PDF document text
    • https://www.demetagras.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607297a2b2eb8---17869690845.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_off000111b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111B1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000129c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x129C8 10876 bytes
SHA-256: a90df2a87d33066c72cf16aa99940208674ad799ca48b7f6ee3edf9aac9ed6f1
font_02_sfnt_off000142aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x142AA 18132 bytes
SHA-256: 5d83f620f80bed410726c9a12ecd61e4ab8cdace4cc0159bbabbec1ad315c876

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