Malicious PDF — malware analysis report

Static analysis result for SHA-256 13a77cd84a455bb0…

MALICIOUS

PDF

69.7 KB Created: 2021-10-04 04:57:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: f43d9bcf297203b739fc29acc7136c11 SHA-1: 53af9973d84f3880eb1d9859e208f6b9308ae63e SHA-256: 13a77cd84a455bb017f0aa8a9c24e8a8474012f7d2a7990ae675191846704d6c
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged as malicious by ClamAV and an ML classifier. It contains embedded JavaScript and a large number of external URIs, many of which are on disposable domains, suggesting a link farm or phishing lure. The presence of embedded JavaScript indicates an attempt to execute code within the PDF viewer, likely to redirect the user to malicious sites or download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9893

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
  • 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 https://catamma.ru/uplcv?utm_term=mass+effect+3+pc+trainer PDF link annotation
    • http://anhuishangbiao.com/upload_fck/file/2021-9-16/20210916221614554342.pdfIn PDF document text
    • http://accessiblevehicleservices.com/userfiles/file/resumamasogeresemiju.pdfIn PDF document text
    • https://fotojursa.cz/userfiles/file/fepatoxodaweviwij.pdfIn PDF document text
    • http://maychaybocaocap.com/app/webroot/uploads/files/87268305399.pdfIn PDF document text
    • http://s4l.vn/storage/ckfinder/files/nadibiloxolojidupekigo.pdfIn PDF document text
    • http://cga82.com/admin/File/memasatofanekizub.pdfIn PDF document text
    • http://roberlo.cz/www/files/file/fotiletovawup.pdfIn PDF document text
    • http://ng-sons.com/userfiles/file/detofiveriloxefovoxudu.pdfIn PDF document text
    • http://tavio.su/files/file/lunivediz.pdfIn PDF document text
    • http://lawngo.net/fckfiles/4033240694.pdfIn PDF document text
    • http://www.smwiarus.pl/ckfinder/userfiles/files/93991017189.pdfIn PDF document text
    • http://sonhanint.com/uploadpic/sun/files/202109270100349701.pdfIn PDF document text
    • http://uptindia.com/newsimages/file///viwejezolezelabirod.pdfIn PDF document text
    • https://anzhero-sudzhensk.verlauf-ekb.ru/admin/ckfinder/userfiles/files/lapol.pdfIn PDF document text
    • http://haohanlegend.com/Uploadfiles/files/kifewulavi.pdfIn PDF document text
    • https://newchat.xyz/js/ckfinder/userfiles/files/lixuvesozexorexomukul.pdfIn PDF document text
    • https://forumhotel.by/wp-content/plugins/super-forms/uploads/php/files/nd14da4gk91g8v75vg7vbatrq5/ligunabimipexez.pdfIn PDF document text
    • http://udelimpa.es/ckfinder/userfiles/files/sadavomatizifenokuroka.pdfIn PDF document text
    • http://opersan.com/file/fedewademupibowo.pdfIn PDF document text
    • https://bibonatura.hu/ckfinder/userfiles/files/69378203276.pdfIn PDF document text
    • https://cosplay-expo.it/ckfinder/userfiles/files/48767514348.pdfIn PDF document text
    • http://quocteanviet.com/img-chamthi/files/76114474441.pdfIn PDF document text
    • http://skene.es/userfiles/file/13297265565.pdfIn PDF document text
    • http://fornacedelia.it/userfiles/files/tesubawaremowotapogeg.pdfIn PDF document text
    • http://www.gonouvellezelande.com/files/nunisijubasogewuxabupimej.pdfIn PDF document text
    • http://kernenshepler.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/dolenewowurabolu.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_off0000b0da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB0DA 10472 bytes
SHA-256: 19ecc792832d8d9f75dbb311db3d246bf4514f94d70b9c55254777ebcfe2d3c7
font_01_sfnt_off0000c8d1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC8D1 15880 bytes
SHA-256: 20418d9698ea6fe981220615eb92a21230c8905dc9b1276ddfcff71959645614
font_02_sfnt_off0000f15b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF15B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1