Malicious PDF — malware analysis report

Static analysis result for SHA-256 cfa9b1a0090e9608…

MALICIOUS

PDF

79.5 KB Created: 2021-09-10 16:19:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 406df2c0de74c9db9ccd6678a375f519 SHA-1: 9d19147aeab138e949167b54c740f98b066bb440 SHA-256: cfa9b1a0090e96087454b260e80cb6ff18e830a9677e77f3aa86bb6117a3ff6b
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating embedded JavaScript and a link farm pointing to potentially compromised WordPress upload storage. The link farm likely serves to obscure the true destination and evade detection, redirecting users to various PDF files hosted on disposable or compromised domains. The embedded JavaScript is likely used to facilitate the redirection or exploit vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://old.arcnet.org.tw/ckfinder/userfiles/files/93449998121.pdf In PDF document text
    • http://lngpetro.com/userfiles/file/77921085763.pdfIn PDF document text
    • http://www.holderit.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613af51fa4524---39845599038.pdfIn PDF document text
    • https://mrdak.cc/uploadfile/files/nekobukarirojalew.pdfIn PDF document text
    • http://xn--80aa5alfu.kz/file/21800419884.pdfIn PDF document text
    • http://klick-tipp.at/ckfinder/userfiles/publics/files/68693774865.pdfIn PDF document text
    • http://aiaato.com/FileData/ckfinder/files/20210909_B3599C9A0B487AEA.pdfIn PDF document text
    • http://tw-tms.com/uploadpic/xw/files/26581710503.pdfIn PDF document text
    • http://fiumevivo.it/userfiles/files/41336897766.pdfIn PDF document text
    • http://twilaw.com/files/files/33597907507.pdfIn PDF document text
    • http://poney-club-romilly-aigre28.fr/userfiles/file/43801483906.pdfIn PDF document text
    • https://renfrewareahealthvillage.ca/ckfinder/userfiles/files/mexuvogegitopizo.pdfIn PDF document text
    • http://dylogistics.com/userData/board/file/bekonirinetunadidimena.pdfIn PDF document text
    • https://www.sensormaticltd.com/app/templates/js/ckfinder/userfiles/files/neranarigalegogagasapaxe.pdfIn PDF document text
    • https://greenline.bg/userfiles/file/solusapozosonozeleba.pdfIn PDF document text
    • https://www.gsccn.it/wp-content/plugins/formcraft/file-upload/server/content/files/16134338253ff6---muwadonojapedolorit.pdfIn PDF document text
    • https://campermagazine.tv/public/file/53516787611.pdfIn PDF document text
    • http://www.ctnphrae.com/ckfinder/userfiles/files/masoxaw.pdfIn PDF document text
    • https://moraure.net/js/ckfinder/userfiles/files/kufafukapopufibunoded.pdfIn PDF document text
    • http://www.hkwebdesign.com.hk/wp-content/plugins/formcraft/file-upload/server/content/files/1613a3ae13fdb0---rudim.pdfIn PDF document text
    • http://smcertificationservices.com/userfiles/files/33103068253.pdfIn PDF document text
    • http://krevue.cz/UserFiles/File/lepilaku.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=how+to+move+data+to+memory+cardPDF 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_off0000d171.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD171 18264 bytes
SHA-256: e7810866c780a9a4a050180b1ad563b48762d2306e7a5618bd114686e7b03db5
font_01_sfnt_off0001015d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1015D 10380 bytes
SHA-256: c9c5119733d98d80582e4826ef4651fbb179f9afd1f6f6f931f79d50b32bc39a
font_02_sfnt_off000118ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118EA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1