Malicious PDF — malware analysis report

Static analysis result for SHA-256 8e958f16753631d6…

MALICIOUS

PDF

86.4 KB Created: 2021-09-09 08:04:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: d7e2f0e7265e4cc51013496c125096f1 SHA-1: 0e6f2ff2f38862fd716819e632ed61047096c454 SHA-256: 8e958f16753631d6b6194a9a434007b1189b28f70d13682b2a6290f7d0f56167
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It functions as a link farm, with numerous URLs pointing to external sites, some of which are hosted on compromised WordPress installations. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://oniceh.ru/uplcv?utm_term=discrete+structures+in+computer+science+pdf PDF link annotation
    • https://interstudy.net/userfiles/file/13294300788.pdfIn PDF document text
    • https://www.hauptsache.cc/wp-content/plugins/formcraft/file-upload/server/content/files/16133bb8ce2e3a---sujukozilemujuso.pdfIn PDF document text
    • http://gartenbaukoeln.de/uploads/files/76375056929.pdfIn PDF document text
    • http://mebel-moscow.com/content/xuploadimages/file/91223056149.pdfIn PDF document text
    • https://accesoriosalmayor.com/images/userfiles/file/59482961292.pdfIn PDF document text
    • http://www.ochoadentalcare.com/tacgestorcontenidos_ochoa/documentos/file/In PDF document text
    • https://areicon.com/images/file/8695853112.pdfIn PDF document text
    • http://hyunshin.net/userfiles/file/39397557912.pdfIn PDF document text
    • https://www.thecandystoresudbury.com/wp-content/plugins/super-forms/uploads/php/files/1n70tsen3ah3g46jro5ap4bdf6/61784960199.pdfIn PDF document text
    • http://miroslaws.com/ckfinder/userfiles/files/55044160615.pdfIn PDF document text
    • http://cungcapbaoduongcuanhatban.com/upload/files/danovimixir.pdfIn PDF document text
    • https://hitourkorea.com/FileData/ckfinder/files/20210901_1D5287B609396460.pdfIn PDF document text
    • http://veronikavilla.hu/userfiles/file/nifofizojanesegesodabul.pdfIn PDF document text
    • http://iweldbot.com/ckfinder/pho/files/18344253362.pdfIn PDF document text
    • https://taybaite.com/userfiles/file/xujezelosapomozukanos.pdfIn PDF document text
    • http://hsi-international.com/ckfinder/userfiles/files/zekep.pdfIn PDF document text
    • http://msslink.ru/userfiles/files/54010325574.pdfIn PDF document text
    • http://salonlomi.pl/wp-content/plugins/formcraft/file-upload/server/content/files/161390768e139c---digodupirozigivowofefoza.pdfIn PDF document text
    • http://progetec.org/userfiles/files/xugonep.pdfIn PDF document text
    • https://www.horisunmauritius.com/wp-content/plugins/super-forms/uploads/php/files/7ec60c87537bb45f3bcb5290d7cad36a/38475063420.pdfIn PDF document text
    • https://nanyangtextile.com/userfiles/file/lolajekube.pdfIn PDF document text
    • http://xn--80akazwaeiw.xn--p1ai/editorfiles/file/43492917732.pdfIn PDF document text
    • http://szpitalstrzelin.pl/userfiles/files/69513228154.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_off0000ecff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECFF 10676 bytes
SHA-256: 891f38492da48c25759a65bac495815a41ce42fb8e39c9c3931ab92265bf9f4f
font_01_sfnt_off00010574.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10574 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011d86.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D86 17572 bytes
SHA-256: b9938627edaa7a26e9742e84d55cf73e5c6c1d732c384c1a775d0c21088bbebc

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