Malicious PDF — malware analysis report

Static analysis result for SHA-256 c763d1c66b3c1537…

MALICIOUS

PDF

96.4 KB Created: 2021-08-14 09:25:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: c8186908a293a2c1d8bd3ae337d0a610 SHA-1: 4023ddf03900b9f298e74522558c7d85bf76a0b4 SHA-256: c763d1c66b3c15379c39ad780eaa8bcf54e6da41c879beeb6adb6010dda41042
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Static analysis revealed it functions as a link farm, containing numerous URLs pointing to other PDF files hosted on compromised websites. This suggests an attempt to manipulate search engine results or distribute further malicious content through a chain of linked documents.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9952

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://www.ddd-iasi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160822ceaa5a2b---26032640803.pdf In PDF document text
    • https://nutricount.cz/UserFiles/File/bamuvawuvulijererawora.pdfIn PDF document text
    • http://www.adanakursmerkezi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079b59f5e0fe---68442099396.pdfIn PDF document text
    • http://www.macrolepidoptera.hu/userfiles/files/rodirujuwoloje.pdfIn PDF document text
    • https://pacpartner.net/images_client//imagesfile/80419318531.pdfIn PDF document text
    • https://ceilford.org/wp-content/plugins/super-forms/uploads/php/files/ae37e73e31362c4d27e3c130f1d6cf2f/buvatipexot.pdfIn PDF document text
    • https://namastehealth.in/wp-content/plugins/super-forms/uploads/php/files/jlse0teg3v6ctu1tbbfo8e3j3s/vinumixixubapizofoge.pdfIn PDF document text
    • https://shoppingplanet.ro/ckfinder/userfiles/files/42666807302.pdfIn PDF document text
    • https://cornerstonelaw.eu/userfiles//file/nakemumuzekojixuwesipamek.pdfIn PDF document text
    • https://pikewallis.no/wp-content/plugins/formcraft/file-upload/server/content/files/1609540c9e27ff---91511758369.pdfIn PDF document text
    • http://metafelix.it/userfiles/files/sasoxavudubowig.pdfIn PDF document text
    • http://igruppe.no/ckfinder/userfiles//files/10322852973.pdfIn PDF document text
    • https://feltshoe.com/userfiles/file/98508523999.pdfIn PDF document text
    • https://cosalesrep.com/wp-content/plugins/super-forms/uploads/php/files/a8639236f98fbcdafacaa72d52441c3c/91824487160.pdfIn PDF document text
    • http://christmaslandint.com/userfiles/ruzajizopaxif.pdfIn PDF document text
    • https://aimtronu.org/userfiles/file/17161336259.pdfIn PDF document text
    • http://jeremypourstarlight.com/clients/5/53/539822683240d2210db56c0084569a8b/File/58270191396.pdfIn PDF document text
    • https://sukhayurveda.in/userfiles/file/pafupigupijodifuronu.pdfIn PDF document text
    • http://przystaneknida.pl/data/aktualnosci_imgs/file/20267063604.pdfIn PDF document text
    • http://fine-cottage.ru/userfiles/files/divaduge.pdfIn PDF document text
    • http://glenbrooksouth1970.com/clients/1/17/17fc1bd13d5538a69f39d58c869d2fc5/File/11820056435.pdfIn PDF document text
    • https://sirikulsteel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a3596992b5a---41047861402.pdfIn PDF document text
    • http://change4best.ru/upload/file/83483299821.pdfIn PDF document text
    • http://www.qookspot.kitchen/wp-content/plugins/formcraft/file-upload/server/content/files/161115ea6b8506---11732114169.pdfIn PDF document text
    • http://ongnuocdenhat.com/upload/files/3049861221.pdfIn PDF document text
    • https://gradeagroup.com/wp-content/plugins/super-forms/uploads/php/files/r09svi85lsa4ufoppksk04nkub/63286815831.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=ejercicios+de+grafomotricidad+para+ni%C3%B1os+de+6+a+7+a%C3%B1os+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_off00010d11.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D11 18980 bytes
SHA-256: 937405f16f0b82b96441fd4b89fda5c96167913a50cfa943b1cfa93858163295
font_01_sfnt_off00013dad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13DAD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000155c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x155C4 11452 bytes
SHA-256: a7bd425b4472133fc3bec61277726af4a7eb27e28fdb0500ae1d9110a1b2fca4