Malicious PDF — malware analysis report

Static analysis result for SHA-256 16d683ff59afa56e…

MALICIOUS

PDF

71.5 KB Created: 2021-09-20 08:04:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 3f48a33edd3d204d417c2da62c01cc7e SHA-1: db4b392ee7efa9c2c161b8563c2159e8f9ba76d5 SHA-256: 16d683ff59afa56e08ed886b127d98e750844b61cbff64dc6c345f77511e3cf3
156 Risk Score

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier, and contains numerous embedded URLs. Several heuristics indicate the PDF acts as a link farm, pointing to compromised WordPress sites and disposable hosting, suggesting a phishing or malware distribution lure. The presence of many external URIs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic strongly support this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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://irlanc.ru/uplcv?utm_term=super+backup+pro PDF link annotation
    • http://yugang360.com/upload_fck/file/2021-9-10/20210910085135110197.pdfIn PDF document text
    • https://gkatsov.com/userfiles/file/4683530049.pdfIn PDF document text
    • https://dbjadow.pl/attachments/file/16234765271.pdfIn PDF document text
    • https://anzhero-sudzhensk.verlauf-ekb.ru/admin/ckfinder/userfiles/files/relamezowixizixojinu.pdfIn PDF document text
    • http://angelofthewinds.org/ckfinder/userfiles/files/mumulegem.pdfIn PDF document text
    • http://www.sbawerribee.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16132ec60333c2---89793775698.pdfIn PDF document text
    • http://tnslib.su/userfiles/files/konodedesukijidi.pdfIn PDF document text
    • http://zbigniewrodak.pl/galeria/file/befusudoliviwisetetize.pdfIn PDF document text
    • http://marthomaiticherukole.com/userfiles/file/daxujavag.pdfIn PDF document text
    • https://kayakbranson.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e97d74eec1---dozewonobediko.pdfIn PDF document text
    • http://agrocare.hu/ckfinder/userfiles/files/pibiruwibabodo.pdfIn PDF document text
    • http://www.insurancedirectcanada.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16146128fc9325---fuketasejefimo.pdfIn PDF document text
    • https://eclearusa.com/images/file/13560239756.pdfIn PDF document text
    • http://backkwang.com/userData/board/file/natadigaboz.pdfIn PDF document text
    • http://kaithompson.com/userfiles/file/16332942458.pdfIn PDF document text
    • https://sv-fin.ru/wp-content/plugins/super-forms/uploads/php/files/12e4108c9f88f5784c8118dd45365f58/wuxewafiseviresowepanu.pdfIn PDF document text
    • http://uklearningnetwork.com/userfiles/file/38455768167.pdfIn PDF document text
    • http://imosa.asia/uploads/files/202109122338309258.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/161d64acb3234d1a1a54e2e2907afd3e/83234530885.pdfIn PDF document text
    • http://gz-theoutfit.com/UploadFiles/FCKeditor/20210919045228.pdfIn PDF document text
    • http://rockycheng.com/ckfinder/userfiles/files/wagajavixi.pdfIn PDF document text
    • https://alwaysthesame.pt/site/upload/file/17960423376.pdfIn PDF document text
    • http://ortopediaszombathely.hu/editor_up/zikekokaj.pdfIn PDF document text
    • https://defi128.com/userfiles/files/95922143488.pdfIn PDF document text
    • http://stowarzyszeniemalyksiaze.eu/img/upload/files/pezexerofosotaxi.pdfIn PDF document text
    • http://cutyoursupport.com/userfiles/file/67338285736.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_off0000b6b6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB6B6 16792 bytes
SHA-256: f2f9e7b7249c84e2e796a9a9dc3bb9eb8dcf6a5e6e80d9c7625b0a2f3e83021e
font_01_sfnt_off0000e197.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE197 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f9ae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9AE 10268 bytes
SHA-256: 7b0adfa39e32c19d05409c4b57978df3218e182e485d7b67382b75b62a36cd06

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