Malicious PDF — malware analysis report

Static analysis result for SHA-256 a82f4299da6b86c2…

MALICIOUS

PDF

80.2 KB Created: 2021-09-13 09:25:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 2dd7876087b92248bab7e64d08e25287 SHA-1: b33519443332f78138750eae78c505fac68b4bd5 SHA-256: a82f4299da6b86c2b63255371643d2ecfb883180e5429dbe564a34be89a917fb
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to external sites, some of which are hosted on compromised or disposable domains. The document body is unreadable binary data, suggesting it's not intended for direct user consumption but rather to host malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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://mtegl.wsystem.sk/userfiles/files/41443462755.pdf In PDF document text
    • https://fwstc.in/userfiles/file/42574562882.pdfIn PDF document text
    • http://pk.mo/userfiles/file/24732444952.pdfIn PDF document text
    • http://barexkft.hu/userfiles/file/59324912181.pdfIn PDF document text
    • https://www.acta-mobilier.fr/ckfinder/userfiles/files/metetuvuwuzebuxebigokem.pdfIn PDF document text
    • http://stefanourso.com/public/userfiles/file/49607628259.pdfIn PDF document text
    • http://gardenofsound.com/userfiles/files/96682732181.pdfIn PDF document text
    • http://for-rent-leuven.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612eac027b57b---dupusojuveduludototoruzil.pdfIn PDF document text
    • http://www.contal-farmer.com/uploads/files/89059127876.pdfIn PDF document text
    • http://a1climbing.com/userfiles/files/sipudipoguvogazamomonol.pdfIn PDF document text
    • http://cluboutletmoto.net/campannas/file/zukajorog.pdfIn PDF document text
    • http://transchem-tech.com/Uploadfiles/files/jevadusisawusuv.pdfIn PDF document text
    • http://logicparcel.net/uploadsEditorfile/guzasovopeki.pdfIn PDF document text
    • https://arnetbilgisayar.com/upload/ckfinder/files/totunurowezogudaveweguj.pdfIn PDF document text
    • https://trucraftsmanship.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613749d1dc515---49047820138.pdfIn PDF document text
    • https://iwanbim.com/userfiles/files/88996036900.pdfIn PDF document text
    • https://energiadirect.pl/application/resources/ckfinder/userfiles/files/25933599619.pdfIn PDF document text
    • http://abnicum.com/files/file/kivabutitabezulozefok.pdfIn PDF document text
    • https://topclassgreenery.nl/images/file/welebu.pdfIn PDF document text
    • http://wabasnb.com/files/fckeditor/file/427118280613e13ce24727.pdfIn PDF document text
    • https://vinocastillo.hu/editor_up/doxewavuvova.pdfIn PDF document text
    • http://safedoorsystems.com/cmsimages/file/nalegazoxejivilewukexo.pdfIn PDF document text
    • https://www.tessilgiada.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613e6b1b9775c---60844545129.pdfIn PDF document text
    • http://op-gold.com/ck_image/files/werabipoxabovudaruvok.pdfIn PDF document text
    • https://toskov-yordanov.com/userfiles/file/99102747836.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=little+house+on+the+prairie+ebook+freePDF 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_off0000d5a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5A7 17176 bytes
SHA-256: 38029b37eb402710f4fcd4bf929f671d7279128653abc44c341c6e62c6dd7eca
font_01_sfnt_off00010271.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10271 10744 bytes
SHA-256: 0bd2ec67bd16f7a16c34bbe90b4f489730f7a998cf722cc84dbe275a64da9131
font_02_sfnt_off00011adc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11ADC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1