Malicious PDF — malware analysis report

Static analysis result for SHA-256 f908c36c4d31b7ae…

MALICIOUS

PDF

75.8 KB Created: 2021-09-17 03:10:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 99759905ecdb86adc29071ac45974d84 SHA-1: 57dae5ee1f67d44633113a18e0c8cd5ec4cf4bbe SHA-256: f908c36c4d31b7aeb4b1cedd15b389a6d08279b7fae21f3fa77d91b3120812f4
126 Risk Score

Malware Insights

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

The sample was detected as malicious by ML classifiers and ClamAV, specifically identified as a phishing trojan. It contains numerous embedded URLs, many pointing to PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a deliberate attempt to create a large number of links on disposable hosting, a common tactic for SEO poisoning or distributing malicious content. While no scripts were explicitly extracted, the nature of the PDF and its embedded links strongly suggests it is used to direct users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://www.tzounakos-insurance.gr/ckfinder/userfiles/files/35869617405.pdf In PDF document text
    • http://vaynhe.com/upload/files/92628505167.pdfIn PDF document text
    • https://sanagustin.cl/files/35917292662.pdfIn PDF document text
    • http://ezclasssites.com/var/wwww/dev-ezclasssites-com/data/files/zupiratomatalaluxujujipi.pdfIn PDF document text
    • http://riggi.ru/userfiles/file/bilikejozafofojigod.pdfIn PDF document text
    • http://irk-yoga.ru/upload/files/jarobuw.pdfIn PDF document text
    • http://szyldkj.com/luodan/images/userfiles/file/18136991335.pdfIn PDF document text
    • http://immobilieninvestors.com/userfiles/file/30483402872.pdfIn PDF document text
    • http://uitvaartverzorgingsindex.nl/images/uploads/ripiz.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/1b3fe72038751a373b1fb2ebca72cd26/manafulobuxukotomo.pdfIn PDF document text
    • http://massimosusto.eu/userfiles/files/dokovew.pdfIn PDF document text
    • http://influences-vegetales.eu/assets/Image/files/72915111063.pdfIn PDF document text
    • https://sma-dfgg.org/site/admin/file/pijab.pdfIn PDF document text
    • http://smwiarus.pl/ckfinder/userfiles/files/vaxuboworodowelagikiwovud.pdfIn PDF document text
    • http://sky1981.com/asset/uploads/files/bojijuguko.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/pu2dlidmgse3ktsm1fekd6d0s3/42242380224.pdfIn PDF document text
    • http://smart-ventures.ch/upload/Editor_Images/files/jalatepisufavunev.pdfIn PDF document text
    • http://linuxnewyork.com/draft/media/gaxodado.pdfIn PDF document text
    • https://gulfcans.com/home/madarmun/public_html/gulfcans/images/bulk_images/files/kupusij.pdfIn PDF document text
    • https://greenlandpark.com/uploads/files/11314568686.pdfIn PDF document text
    • http://gzcil.com/uploadfile/files/62279973600.pdfIn PDF document text
    • http://bcslaw.hu/admin/fck_upload/file/64786577097.pdfIn PDF document text
    • http://centralgiving.com/media/userfiles/file/88657962142.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=mkvking+app+download+apkPDF 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_off0000bfdf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBFDF 19396 bytes
SHA-256: c3ed016ef25a554af00090aa38d92d3e015a397a568f95346f589ff661b749d6
font_01_sfnt_off0000f305.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF305 10308 bytes
SHA-256: c65ffe312248b02bdf8bb233494f531c602c55b467716794fa53daea2503d92b
font_02_sfnt_off00010a1f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A1F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1