Malicious PDF — malware analysis report

Static analysis result for SHA-256 cdcf76dac69fd3d3…

MALICIOUS

PDF

86.2 KB Created: 2021-07-08 19:52:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: b435aa696c03be427e527c972b0713b8 SHA-1: 40da27d12d3c440c37a332fa157f9a1c12b0d03f SHA-256: cdcf76dac69fd3d30dba21a44031a92b309146dace78efb43f266cb664f82dd5
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document that contains a large number of external links, many pointing to compromised WordPress sites. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware. 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 0.9947

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://queure.ru/uplcv?utm_term=best+pdf+to+word+converter+app+for+android PDF link annotation
    • https://xn--80aaijz0c.xn--p1ai/ckfinder/userfiles/files/sebaxazatuvade.pdfIn PDF document text
    • http://mijneigenlift.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160765f1de053b---zusave.pdfIn PDF document text
    • http://wakingbeauty.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c5bf3c6bbc---10338568482.pdfIn PDF document text
    • https://fortlauderdale-carservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c96957efa48---85118500923.pdfIn PDF document text
    • https://anpheatingandac.com/nbloom/fckuploads/file/73788564325.pdfIn PDF document text
    • https://micsys.in/userfiles/file/pitejovelamusituwege.pdfIn PDF document text
    • http://doublehappyvstheinfinitesadness.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a69747b6480---24009498210.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160bdb5c98c972---losixewelala.pdfIn PDF document text
    • http://zgic.ru/!upload/files/nuseremidegunowete.pdfIn PDF document text
    • http://mynigaoe.com/upload/file/20210607192318.pdfIn PDF document text
    • https://singaporenotarypublic.com/wp-content/plugins/super-forms/uploads/php/files/5b271734971e170906774f132fd5bdd8/85981320901.pdfIn PDF document text
    • https://wscnaturalhealings.com/wp-content/plugins/super-forms/uploads/php/files/42bbd9948c78618ca5d4573f41ed0e58/jagibopixumugegenamur.pdfIn PDF document text
    • http://keralabiblesociety.com/fck_uploads/file/12462569808.pdfIn PDF document text
    • http://cck-brno.cz/ckfinder/userfiles/files/woxumeripakixubivimosafu.pdfIn PDF document text
    • http://inlikeflintlogistics.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078c209e9e76---3199226780.pdfIn PDF document text
    • http://aeskulap24h.de/wp-content/plugins/formcraft/file-upload/server/content/files/160add0105310b---3672447989.pdfIn PDF document text
    • https://dezsredstvompx.ru/wp-content/plugins/super-forms/uploads/php/files/0c1743034db4487d3361289f829fd5e4/majosomajiwiwunamexadogap.pdfIn PDF document text
    • http://fitnessklub-impuls.pl/uploads/assets/file/wuduxubomed.pdfIn PDF document text
    • https://harpethvalleyhealth.com/wp-content/plugins/super-forms/uploads/php/files/fc6bccd463d29779b62558cdc142ffab/54799330454.pdfIn PDF document text
    • https://martybermanassociates.com/wp-content/plugins/super-forms/uploads/php/files/5288cb9b42d2fe44a64b78bae9c12251/pewoxixevolitiro.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608dfb55dd6d5---85204021370.pdfIn PDF document text
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/ietm6imvqns328m41sjp78hl17/gejifijoxuvif.pdfIn PDF document text
    • http://principessavencanice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160795f2bc7713---59637688973.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160962234c9da3---47513037776.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_off0000eeae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEAE 16840 bytes
SHA-256: 5d9976d6792a9ee317957a4c39c3604043c4cfeda5a04e6be3ee81ea8035f26e
font_01_sfnt_off00011a0f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A0F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013226.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13226 10772 bytes
SHA-256: 6b95c896216005be642738677b4f8de5d7c85a77ddc519781cfedaf4464944b3

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