Malicious PDF — malware analysis report

Static analysis result for SHA-256 3be1855e17999bcf…

MALICIOUS

PDF

86.3 KB Created: 2021-09-14 08:17:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 631213892db422066ba7fccb5038a80b SHA-1: a131e203183d0dc855de386c4ebb5936c63914ac SHA-256: 3be1855e17999bcfd66c1b6cd0229493127fb9dae03a348e35ad56db5d8e8529
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm or phishing attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. Although no scripts were directly extracted, the PDF structure and embedded URLs are indicative of a malicious document, likely delivered as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://bk.knu.ac.kr/ckfinder/userfiles/files/temusedi.pdf In PDF document text
    • https://luiginoiobbi.com/userfiles/file/nevufomadig.pdfIn PDF document text
    • https://latework.cz/soubory/1294375428.pdfIn PDF document text
    • https://marbeyoyun.com/calisma2/files/uploads/27970312658.pdfIn PDF document text
    • http://taispacedesign.com/upload/files/86670706821.pdfIn PDF document text
    • https://quangcaowebsite.xemlaco.com/uploads/files/lunozadogabojuvewepen.pdfIn PDF document text
    • http://www.kymkarajok.net/tiedostot/files/jasepanunuxikobenov.pdfIn PDF document text
    • http://oneself.pro/wp-content/plugins/formcraft/file-upload/server/content/files/1613907839d85a---lujaxatilenosuna.pdfIn PDF document text
    • http://xn--9w3b270a7kf.kr/ckfinder/userfiles/files/27000905165.pdfIn PDF document text
    • http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613593b00baf7---12288960499.pdfIn PDF document text
    • http://apart1day.ru/file/xozurapi.pdfIn PDF document text
    • https://www.chablis-gautherin.com/ckfinder/userfiles/files/6967808508.pdfIn PDF document text
    • http://www.guus.edu.mn/ckfinder/userfiles/files/88703929221.pdfIn PDF document text
    • http://fli.edu.mn/ckfinder/userfiles/files/39759070268.pdfIn PDF document text
    • https://www.formwork.co.uk/wp-content/plugins/super-forms/uploads/php/files/7h6il4lof891nfh60duhjp45v1/26054884167.pdfIn PDF document text
    • http://paneldeconso.com/userfiles/file/zivozoxag.pdfIn PDF document text
    • https://mwasafat.com/uploads/files/20567008905.pdfIn PDF document text
    • http://www.cuadernos.in/wp-content/plugins/formcraft/file-upload/server/content/files/1613fedd29419c---gines.pdfIn PDF document text
    • https://pyhm.ca/wp-content/plugins/super-forms/uploads/php/files/k7gdhgeujk1s6pqc56ghgu7480/zajupatinaferimizerefixe.pdfIn PDF document text
    • http://franklcalabreseattorney.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/zumejiwuwuv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=android+app+development+using+flutterPDF link annotation
    • http://kioskcondoweb.wpengine.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136a25a5732d---66893175577.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_off0000e954.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE954 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001016b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1016B 10988 bytes
SHA-256: 2ef1b0ef88e9383077511f65cdd46adadfe25ec6cb255bfd79e64719b559e440
font_02_sfnt_off00011abd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11ABD 18576 bytes
SHA-256: b5ba2a2b25b6f8221605bfcaa8abf3e1326a2a76e0de309c640ccaa21bf6e17d