Malicious PDF — malware analysis report

Static analysis result for SHA-256 cd3b9e3d115b5dbd…

MALICIOUS

PDF

87.9 KB Created: 2021-09-21 20:03:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 5b474abb58f7dacf089294ec234560a4 SHA-1: 7a2570f7470d94faa375e49f0aaa1a874bddfe89 SHA-256: cd3b9e3d115b5dbdb0285deaa5189d26a6e4b2478f66cdd27f221b2bd535cca7
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URIs and links to compromised WordPress upload storage, suggesting it's part of a link farm designed to redirect users to malicious sites. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this, indicating the PDF's primary function is to host and distribute links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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 https://krisoc.ru/uplcv?utm_term=watch+full+hd+movies PDF link annotation
    • https://popcouncilinstitute.org/wp-content/plugins/super-forms/uploads/php/files/9d36be6dcc0056db09baa27c22268bc4/17026891943.pdfIn PDF document text
    • https://7foro.exceltur.org/exceltur_nuevo/ckfinder/userfiles/files/tabaj.pdfIn PDF document text
    • https://eijo.in/ckfinder/userfiles/files/jewojelo.pdfIn PDF document text
    • http://riccaassociati.eu/userfiles/files/47077026612.pdfIn PDF document text
    • https://tutorsbureau.net/userfiles/file/36832086704.pdfIn PDF document text
    • http://hooleihomes.com/cms_images/file/bedexoriden.pdfIn PDF document text
    • http://abbuffalowings.com/uploads/files/kedara.pdfIn PDF document text
    • http://apmnir.ro/fckfiles/file/23663561569.pdfIn PDF document text
    • http://cappellastudio.it/userfiles/files/49954151317.pdfIn PDF document text
    • http://gourmethousemacau.com/UploadFilesfile///57498846250.pdfIn PDF document text
    • https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/mn0inhhbq05fo6b0smt1555kpq/lamilojatavogipak.pdfIn PDF document text
    • http://aceonlinementors.com/userfiles/file/pidimaf.pdfIn PDF document text
    • https://laptopserwis.com/app/webroot/media/files/tabewejerikita.pdfIn PDF document text
    • http://chicagohalo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135bd2e93a9e---73085644195.pdfIn PDF document text
    • https://zoldlaptop.hu/ckfinder/userfiles/files/saselilin.pdfIn PDF document text
    • http://land89.com/ckupload/files/81266281430.pdfIn PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16131feacb79d6---dulekizisanalazesu.pdfIn PDF document text
    • http://boldogelet.hu/media/xegikata.pdfIn PDF document text
    • http://fgosvo.ru/files/files/88322049375.pdfIn PDF document text
    • http://bibliotekaludwin.pl/img/upload/files/41490467929.pdfIn PDF document text
    • http://33podarka.ru/pictures/files/8784893367.pdfIn PDF document text
    • https://sipare.com.ar/wp-content/plugins/super-forms/uploads/php/files/i3k61u21drlemisb6s2dj0cjil/tijereb.pdfIn PDF document text
    • https://vr-spagna-20.effievirtual.com/galeria/files/90231950635.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_off0000f446.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF446 17596 bytes
SHA-256: 2d2b8fd2127d8e74efd67991f575fcf1d7bff8f5914ba91810bc8a05854042cd
font_01_sfnt_off0001218e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1218E 10696 bytes
SHA-256: cd0c14d2283b96635691272b88fae450df6085f15060baf0eb1e950831b05c80
font_02_sfnt_off00013a34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A34 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1