Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef3b07cefb962c25…

MALICIOUS

PDF

90.1 KB Created: 2021-08-21 22:33:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 8a5a77c61ef8ccfd82d50030236a457d SHA-1: 359d48456cbbe1d5aa3c0fa06955f6e4405f8bfc SHA-256: ef3b07cefb962c25dda73f9b0586967b398a0bf16b4f7636cf647df387ddc078
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample contains embedded JavaScript, which is a common technique for executing malicious code within PDFs. It also features a link farm pointing to multiple distinct hosts, many of which appear to be compromised WordPress sites or disposable hosting, suggesting an attempt to obscure the ultimate destination or evade detection. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://liily.jp/upload/file/20210728055837.pdf In PDF document text
    • http://sbstroy53.ru/img/files/21244922384.pdfIn PDF document text
    • https://pfgmm.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607630c03f7dc---zizevuzazowutopavixukemam.pdfIn PDF document text
    • http://binhchuachay.info/Images_upload/files/25412413189.pdfIn PDF document text
    • https://sellos-mecanicos.com/wp-content/plugins/super-forms/uploads/php/files/a790e49bbadc79f4b24b25ebbe0ba58d/nofonutemidoxa.pdfIn PDF document text
    • https://blugarden.eu/file/95681623831.pdfIn PDF document text
    • http://www.meglobalinc.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160e5a90b306f3---36474139925.pdfIn PDF document text
    • https://empezo.xyz/js/ckfinder/userfiles/files/83681260326.pdfIn PDF document text
    • http://taitung-house.com/CKEdit/upload/files/nuxuvevu.pdfIn PDF document text
    • http://artecgroupservices.com/imagenes/file/lilarapekekezuses.pdfIn PDF document text
    • https://www.autopsrus.com/ckfinder/userfiles/files/zosibawamajim.pdfIn PDF document text
    • http://cps-mbstu.edu.bd/app/webroot/js/ckfinder/userfiles/files/gunajutojilozomi.pdfIn PDF document text
    • http://travisreunion.com/clients/1/1d/1d9c560ef9ee6310b862f4c9d288d7bd/File/40679566336.pdfIn PDF document text
    • https://dentinale.eu/wp-content/plugins/super-forms/uploads/php/files/6aee199368abd47c665986b550c53445/vaxuvagugisenawujujuwa.pdfIn PDF document text
    • https://samajsutra.com/userfiles/files/jiwogokozepi.pdfIn PDF document text
    • http://go-trec.com/wp-content/plugins/super-forms/uploads/php/files/fpdhm1sidbip1kk3ul9l9bevql/12972480772.pdfIn PDF document text
    • http://badaranquehablar.com/userfiles/files/71385200884.pdfIn PDF document text
    • http://www.melodypods.com/wp-content/plugins/formcraft/file-upload/server/content/files/1611cebdc093c2---2768687705.pdfIn PDF document text
    • http://chieusangducphat.com/uploads/userfiles/file/6174239902.pdfIn PDF document text
    • https://grafitpoint.ru/wp-content/plugins/super-forms/uploads/php/files/bc83d655f3f31ecbb0c7feaaf52ab1fb/72120904751.pdfIn PDF document text
    • http://munsusa.org/userfiles/file/20210618152313.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=ventajas+y+desventajas+del+aprendizaje+basado+en+problemas+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_off0000fc83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC83 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001149a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1149A 11136 bytes
SHA-256: 849c1969db33f0990da44ad16e9acb6cbc35a887bbb85587cf33c9cc892729fa
font_02_sfnt_off00012e6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E6A 16904 bytes
SHA-256: be42e496312275d3bab49e50e45851da93a184853e77749eabd7e872336f1e42

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