Malicious PDF — malware analysis report

Static analysis result for SHA-256 91e83ca6db1bbd29…

MALICIOUS

PDF

87.6 KB Created: 2021-09-08 22:57:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: b8bf8719da6758d8ef0baef6e0ee2dd0 SHA-1: 315ac70dffba4cc3156e1f0db303adca4e9f98ea SHA-256: 91e83ca6db1bbd29917ae62db332c70972a237fa442c618bb47acb0d3c7f8134
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The presence of numerous external URIs, many pointing to PDF files, suggests a link farm designed to redirect users. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically highlights the nature of these links, indicating a tactic to obscure the ultimate destination, likely an APK download lure as suggested by the 'utm_term' parameter in one of the URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

Heuristics 5

  • 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.
  • 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://ketchas.ru/uplcv?utm_term=apk+download+latest+version PDF link annotation
    • https://haysalon.com/public_html/userfiles/file/nalerimisavajixuz.pdfIn PDF document text
    • https://autonoleggioassereto.com/file/68774615090.pdfIn PDF document text
    • http://zhongjiukeji.com/upload_fck/file/2021-9-3/20210903121830801464.pdfIn PDF document text
    • https://villanakarin.com/userfiles/files/10065348892.pdfIn PDF document text
    • http://dvg.asia/ckfinder/uploadfiles/files/sepefoselizojig.pdfIn PDF document text
    • https://muguet.fr/sites/default/files/file/dikepup.pdfIn PDF document text
    • http://dalhousieretreat.com/cote_dor_import/admin/ckfinder/userfiles/files/64840234344.pdfIn PDF document text
    • http://lindendirect.com/tempimg/file/rugovaloxed.pdfIn PDF document text
    • https://smshealthcareservices.com/ckfinder/userfiles/files/kenovebixizetusavamawibaj.pdfIn PDF document text
    • http://bradhelferlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/rorafaketasepubefewolizu.pdfIn PDF document text
    • http://isspskola.lv/userfiles/files/gapisoromibemofavine.pdfIn PDF document text
    • http://sp2wronki.pl/fotki/fotki/file/76174847266.pdfIn PDF document text
    • http://jr.ac.th/ckfinder/userfiles/files/15553951415.pdfIn PDF document text
    • http://kondicionery-elektrostal.ru/upload_picture/file/47311989813.pdfIn PDF document text
    • https://alate.org/admin/fckeditor/editorfile/11968174091.pdfIn PDF document text
    • http://emploi.nat.tn/ckeditor/ckfinder/userfiles/files/dagovefumube.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/16132e59b9f8c0---30168455531.pdfIn PDF document text
    • http://www.webtony.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613275f0544d2---27849532629.pdfIn PDF document text
    • http://indcms.testingmachines.com/images/file/96094711722.pdfIn PDF document text
    • http://scenekunstskolen-efteruddannelsen.dk/ckfinder/userfiles/files/lazamirowebasoj.pdfIn PDF document text
    • http://3bbb.fr/ckeditor/upload/files/76115773490.pdfIn PDF document text
    • http://embeddedhr.com/ckfinder/userfiles/files/tafaxogekew.pdfIn PDF document text
    • http://www.louthadventures.ie/wp-content/plugins/formcraft/file-upload/server/content/files/16136a42bed994---74211012050.pdfIn PDF document text
    • http://hengtongrongshang.com/jingkelun/userfiles/files/20210901052638.pdfIn PDF document text
    • https://newegys.egyseg.eu/ckfinder/userfiles/files/sutetiwalofixenidesobelu.pdfIn PDF document text
    • https://studybrilliant.online/app/webroot/img/userfiles/file/71139378772.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_off0000ed4c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED4C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010563.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10563 10608 bytes
SHA-256: 91d239b47b9ab198aa12815ada480234c0f1c3708530665545aeb6e03672c1ce
font_02_sfnt_off00011ddf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DDF 19396 bytes
SHA-256: 0eaaa33dc9f53cac169cc0418ebcd663c0046e41f67d986c8671cb4b85fd69e8