Malicious PDF — malware analysis report

Static analysis result for SHA-256 57b455f6a2cec3c7…

MALICIOUS

PDF

91.7 KB Created: 2021-09-17 05:31:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-07
MD5: 963231d338a0a7ce961e31d904bc1c96 SHA-1: 0b2433fe6426af077bd80bf72b41bd9900eb38cb SHA-256: 57b455f6a2cec3c719ee936000f08ce099ca06d3cd157d51ad286ee21046129f
134 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 numerous external URIs, many of which point to PDF files hosted on various domains, indicating a link farm. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests this is an SEO poisoning or content farm tactic. The embedded JavaScript likely facilitates the redirection or further payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://kubermatkaplay.com/ckfinder/userfiles/files/dakigazezubi.pdf In PDF document text
    • http://centreforeffectivecoaching.com/media/file/kudire.pdfIn PDF document text
    • https://codecs.ro/images/file/94273151292.pdfIn PDF document text
    • https://safetypadlocks.eu/eurostyl/photos/file/15965357545.pdfIn PDF document text
    • http://chiron-ventures.com/chiron/home/img/upload/files/2109120112303959889807d.pdfIn PDF document text
    • https://www.babetravelling.com/ckfinder/userfiles2/files/31673741431.pdfIn PDF document text
    • http://twtqedu.com/userData/ebizro_board/file/19301711637.pdfIn PDF document text
    • http://sumtinathholidays.com/admin/uploadfiles/file/8937593399.pdfIn PDF document text
    • http://enotecagaribaldi.it/userfiles/files/82251305255.pdfIn PDF document text
    • http://hardiebase.com/uploads/assets/filefile/poforutotinavaxiponi.pdfIn PDF document text
    • http://music-summer-courses.eu/upload/files/zelididurubapasu.pdfIn PDF document text
    • http://cathyourhair.nl/js/ckfinder/userfiles/files/baluvazurib.pdfIn PDF document text
    • http://archidaldegan.eu/userfiles/files/foninakesabenamuwe.pdfIn PDF document text
    • https://srilangkapools.com/contents/files/xopij.pdfIn PDF document text
    • https://haciendaloscipreses.cl/upload/file/31665766114.pdfIn PDF document text
    • http://temple.mo/userfiles/file/xajolokifuvoxuwisemajemax.pdfIn PDF document text
    • https://farsiherbal.com/cache/fck_files/file/61217125239.pdfIn PDF document text
    • https://www.conkite.com/wp-content/plugins/super-forms/uploads/php/files/71f1b05fc983fd195356684f888d15f2/71188774821.pdfIn PDF document text
    • http://finance-bulldog.cz/UserFiles/File/50021661387.pdfIn PDF document text
    • http://jtylek.pl/Upload/file/20739442900.pdfIn PDF document text
    • http://www.ktgroup.co.uk/ckfinder/userfiles/files/59788130802.pdfIn PDF document text
    • http://ilovehikari.com/uploads/files/76549658321.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=it+chapter+2+full+movie+2019+freePDF 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_off0001023c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1023C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011a53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A53 11052 bytes
SHA-256: 6f15318459a93f686ebb073d506a5b31ee0f5b1709d2bce654c6e8bae9b2535c
font_02_sfnt_off00013426.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13426 17228 bytes
SHA-256: 4e6ecbe85584c859088a17af0dbe1657d4717df775a92ff022ea5f99052af11a

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