Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bd0e80ca1750ec…

MALICIOUS

PDF

74.3 KB Created: 2021-09-23 23:17:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 4e7f3925b159e532e1d689dd1973e475 SHA-1: 37bb65a1d036423998bfbe511f10744629e5ca2b SHA-256: 81bd0e80ca1750ec1cfd18c764050f8e70271fc29f3d977dada186cf8057f041
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics as malicious, including a high ML score and ClamAV detection. It functions as a link farm, with numerous URLs pointing to potentially compromised websites or disposable hosting, suggesting an attempt to lure users to malicious content. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics indicates a tactic to obscure the true destination or leverage compromised infrastructure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 http://bookblog.kr/data/file/files/bamomovusi.pdf In PDF document text
    • http://studiodebiaggi.eu/userfiles/files/pimir.pdfIn PDF document text
    • http://finadev-groupe.com/userfiles/file/dobarupusivebujikaw.pdfIn PDF document text
    • http://csc0516.com/userfiles/file/20210917114856_o5poga.pdfIn PDF document text
    • http://wu-pao.com/upfiles/editor/files/difumekotegijejo.pdfIn PDF document text
    • http://nhahanghienminh68.com/upload/files/wojilazosizusum.pdfIn PDF document text
    • http://abpjseah.news-read.com/upload/files/94343579533.pdfIn PDF document text
    • https://tavio.ru/files/file/mogetevegurijuvojago.pdfIn PDF document text
    • http://ekachaiguitarist.com/ckfinder/userfiles/files/90847735552.pdfIn PDF document text
    • https://www.hs-hofgastein.salzburg.at/ckfinder/userfiles/files/31806732626.pdfIn PDF document text
    • http://tjsyjdq.com/v15/Upload/file/2021951145411727.pdfIn PDF document text
    • http://sdtrafficticketlawyer.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/643232448.pdfIn PDF document text
    • https://fortworthdental.net/cmsCart/upload/file/venonujuwidejupi.pdfIn PDF document text
    • http://pitchdecor-construction.com/user_img/files/wijiwurika.pdfIn PDF document text
    • http://brlairport.com/images/file/39436745566.pdfIn PDF document text
    • https://www.stnedu.com/ckfinder/upload/files/32284445789.pdfIn PDF document text
    • http://iaestedresden.de/userfiles/file/86800403139.pdfIn PDF document text
    • http://www.trimbleexpress.sk/wp-content/plugins/formcraft/file-upload/server/content/files/1614c6fd7e2135---pinuranigisiwumepox.pdfIn PDF document text
    • http://www.majorisinvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613e79bf9cacf---72455465679.pdfIn PDF document text
    • https://devcons.org/uploads/userfiles/files/42839032935.pdfIn PDF document text
    • https://designmaster.in/scgtest/eec-new/codelibrary/ckeditor/ckfinder/userfiles/files/nesijomuvaxaxobumovo.pdfIn PDF document text
    • https://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1613663fd1beec---56806375109.pdfIn PDF document text
    • http://altaprecision.com/userfiles/file/59114756575.pdfIn PDF document text
    • http://cuatro-pr.org/sites/default/files/file/jikir.pdfIn PDF document text
    • http://hmondo.com/userData/board/file/fepujodifefimolewolifu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=malala+yousafzai+biography+pdfPDF 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_off0000be54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBE54 10852 bytes
SHA-256: 4c830036cca5a19c2fdd538a87c62be33d2c90af35e8f7f749a1963a3c5afb07
font_01_sfnt_off0000d719.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD719 17368 bytes
SHA-256: c0dc9eb60260d03fd679223580ec9903e554ebab16631ca6f7a46260a853f160
font_02_sfnt_off00010359.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10359 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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