Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4bfa094d5f73936…

MALICIOUS

PDF

78.6 KB Created: 2021-09-10 11:52:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 8fb5f265b27fd81c6e4f10f1fee1e889 SHA-1: 06d27a34d6dcbc0ce1202124ba10b58697daa551 SHA-256: a4bfa094d5f7393630c9fff621f0e6be0c82727087f7876987f111c17ea9e765
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains embedded JavaScript and a link farm with numerous URLs, many of which point to other PDF files hosted on potentially compromised websites. The presence of embedded JavaScript suggests an attempt to execute malicious code, likely to download further payloads or facilitate phishing. The link farm structure is a common tactic for distributing malicious content or redirecting users to phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

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 https://queure.ru/uplcv?utm_term=asphalt+9+legends+mod+download PDF link annotation
    • http://asdgolfclubtoscana.com/writable/public/userfiles/file/76895421058.pdfIn PDF document text
    • http://kmconlinecme.com/userfiles/file/24054875609.pdfIn PDF document text
    • http://ooexperience.be/assets/Image/files/bedutafive.pdfIn PDF document text
    • https://mamo-tato.ro/userfiles/file/63026198616.pdfIn PDF document text
    • http://cuacuongiare.vn/upload/files/favututosujesifati.pdfIn PDF document text
    • http://xsteelstock.com/d/files/reximubejok.pdfIn PDF document text
    • http://www.insight-assessment.com/ckfinder/userfiles/files/83440424869.pdfIn PDF document text
    • http://multiflex.ru/userfiles/file/81732725156.pdfIn PDF document text
    • https://immo-cjeanpaul.lu/userfiles/files/61812213263.pdfIn PDF document text
    • http://www.linkkorea.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/16132c30bb03f5---73758915027.pdfIn PDF document text
    • https://www.premiumtrade.ro/ckfinder/userfiles/files/33843766176.pdfIn PDF document text
    • http://canavesiobruno-architetti.it/userfiles/files/11566494293.pdfIn PDF document text
    • http://paoladebenedetti.eu/userfiles/files/kukijezenafur.pdfIn PDF document text
    • https://backcountryplayground.com/wp-content/plugins/super-forms/uploads/php/files/9e87f966641a9c4d7316221effff575e/devam.pdfIn PDF document text
    • https://dpt-mh.com/uploads/news/files/46852478080.pdfIn PDF document text
    • http://etepi.pt/js/ckfinder/userfiles/files/pibubiw.pdfIn PDF document text
    • https://jasz-pap.hu/UserFiles/file/difujomakujebiduje.pdfIn PDF document text
    • https://dukra.sk/editor_uploads/files/zigapifis.pdfIn PDF document text
    • https://pfgmm.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613aa91f4a774---jemuleka.pdfIn PDF document text
    • https://banderlogclub.ru/Files/file/mojukibuvomumiwixifapi.pdfIn PDF document text
    • https://fairtradeportal.pl/userfiles/file/50584800542.pdfIn PDF document text
    • http://omniatel.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613aea0381d84---97685373751.pdfIn PDF document text
    • https://cafesca.mx/ckfinder/userfiles/files/lotobizivifujilaf.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_off0000cd99.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD99 18416 bytes
SHA-256: e1b9e323fe828de821542f80d058fe16062144b6733de36d5795ca0d9583ea1c
font_01_sfnt_off0000fc53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC53 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001146a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1146A 10880 bytes
SHA-256: 710194893b5ba04a5b6b2cca81f347872869e5e1233a7ae50d09abda46419136

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