Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b25a891cb816db…

MALICIOUS

PDF

83.0 KB Created: 2021-06-26 00:06:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: dd5a62c1c4f834200fddfd81e79a08b6 SHA-1: 991ab24edbb5a371da1219daf4337dd55fa73ed9 SHA-256: 81b25a891cb816db63dde2a22512835051d348a7d8638f3ab8fb2a2563c411cf
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of links pointing to compromised WordPress sites, many of which host other PDFs. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The PDF structure and link farm behavior are consistent with a malicious document designed to lure users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

Heuristics 6

  • 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 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://abril.pe/wp-content/plugins/super-forms/uploads/php/files/f6jjpreos0qsga0khbkehbajck/xerobuji.pdf In PDF document text
    • https://mamproducciones.es/wp-content/plugins/formcraft/file-upload/server/content/files/1609874feacb4e---wixanurevesexoledewiwe.pdfIn PDF document text
    • https://ngusacdon.com/upload/files/zewubazujizomevoxas.pdfIn PDF document text
    • http://pericosrentcar.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/16073fd02151cb---rexopanivixexepezabito.pdfIn PDF document text
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b2726e075eb---xupuxulebujuk.pdfIn PDF document text
    • https://udachi.co.th/wp-content/plugins/super-forms/uploads/php/files/ksu27u47dfb6366nklp5200duf/luzofiterirajizodubefe.pdfIn PDF document text
    • http://elonsummerstorage.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608acf62103fa---wanipekogijoxu.pdfIn PDF document text
    • https://skyfireconsulting.com/wp-content/plugins/super-forms/uploads/php/files/c7gdl9sd5bosnjqq4hge4ckov2/dikejegavatelexogatozeg.pdfIn PDF document text
    • https://frontlinetherapist.com/wp-content/plugins/super-forms/uploads/php/files/58ce318477502dfce9f41144589a3d74/xasorabaxijotiwawokoda.pdfIn PDF document text
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/a92383277e411d121aca94753c1e00eb/jonimotita.pdfIn PDF document text
    • https://kassa-evotor.ru/wp-content/plugins/super-forms/uploads/php/files/9sc0tjsjlq1c551kdk689q7oc4/bidegajubuv.pdfIn PDF document text
    • http://bsinteriordesigner.com/userfiles/files/pifopurazenexosutinuxoj.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16073e2aeac7fb---96630940382.pdfIn PDF document text
    • https://www.hauptsache.cc/wp-content/plugins/formcraft/file-upload/server/content/files/160a4bcda642b4---dotatewonipebanozodubok.pdfIn PDF document text
    • https://www.hintonassociates.com/wp-content/plugins/super-forms/uploads/php/files/d65a9ba41af610813400b331dd0464ac/421002356.pdfIn PDF document text
    • https://sdyh.gr/wp-content/plugins/super-forms/uploads/php/files/h05c249eeu7770ul2u2bf6ko70/bixezekodokune.pdfIn PDF document text
    • https://asharfilalkulfi.com/ckfinder/userfiles/files/56240708401.pdfIn PDF document text
    • http://thm-holding.ru/wp-content/plugins/super-forms/uploads/php/files/6dd13f9898409d64444d5f290caa5210/zuzami.pdfIn PDF document text
    • https://cor.org.ar/wp-content/plugins/super-forms/uploads/php/files/mg3br11s0s4jiqkng8vrjguveb/68136226553.pdfIn PDF document text
    • http://www.timtransportes.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/16091c5edb7525---41470403814.pdfIn PDF document text
    • https://leicht-spb.ru/wp-content/plugins/super-forms/uploads/php/files/6573e7b3808557cb4bb06f718b41b406/41800449746.pdfIn PDF document text
    • http://salkim.com/userfiles/file/raxofugazopuvasaxoditir.pdfIn PDF document text
    • http://mesotects.com/wp-content/plugins/formcraft/file-upload/server/content/files/160853a43143e1---fabedikubudadotar.pdfIn PDF document text
    • https://weblative.com/wp-content/plugins/super-forms/uploads/php/files/dqtc560a9es48hg8phup7gk8hi/92588514220.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ec2ed44e07---78884372233.pdfIn PDF document text
    • http://princeverma.in/uploads/files/revuvobiliwotepuvuvatazuv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=cds+2020+previous+year+question+paperPDF 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_off0000e16d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE16D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f984.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF984 11036 bytes
SHA-256: 18313f45a3a5d1d165678be7dac259b1a0e8ba36e21cbb3751b5d204ac549855
font_02_sfnt_off00011337.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11337 16576 bytes
SHA-256: 29aa77bc98f683d5a6d42baca0c9d2644f287607decc0026bb0610985e0f701b