Malicious PDF — malware analysis report

Static analysis result for SHA-256 21bf2171ea9c3166…

MALICIOUS

PDF

77.8 KB Created: 2021-09-06 13:08:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: c98ed29621f546cd890715eb8f9f009c SHA-1: ba3144cb408e607b909588f29409a7ca746764e0 SHA-256: 21bf2171ea9c3166c883bbfa6e146867efcc50ea16caebda4920e743b9f492f0
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs, many of which point to compromised WordPress installations and disposable hosting, indicating a link farm designed to lure users to malicious sites. ClamAV and ML classifiers strongly indicate maliciousness, with the primary attack pattern being the distribution of malicious links. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • 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.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160898549a9fd9---gilutodilezidutap.pdf In PDF document text
    • http://samsung-service-center.ru/uploads/files/46031405847.pdfIn PDF document text
    • https://vanchuyenduongsat.vn/upload/files/xipalazuvaxenelapisinef.pdfIn PDF document text
    • https://alshaabcoop.com/userfiles/file/57493472000.pdfIn PDF document text
    • https://gs-hemeringen.de/ablage/userfiles/files/41458834808.pdfIn PDF document text
    • http://thermocomfort.ca/userfiles/file/30561521325.pdfIn PDF document text
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f35094236f---27668227760.pdfIn PDF document text
    • https://ficsllc.com/wp-content/plugins/super-forms/uploads/php/files/5vaq3vvbbmv263ipna7nessrce/karofipajarusukixulok.pdfIn PDF document text
    • https://icon-studios.com/userfiles/file/69870443412.pdfIn PDF document text
    • http://autokolcsonzoszolnok.hu/admin/fck_upload/file/jexalizizewepiv.pdfIn PDF document text
    • http://businessvaluationapp.com//fck_files/file/34293920235.pdfIn PDF document text
    • http://yourtruck.be/upload/ckeditor/file/81506858097.pdfIn PDF document text
    • https://beaufortbond.com/wp-content/plugins/super-forms/uploads/php/files/33925076fea1198b2bafc183d0e17d06/jofakavadebewosataguzegi.pdfIn PDF document text
    • http://xn--hy1bt45apoap01a.net/jangheung/userfiles/file/49529909850.pdfIn PDF document text
    • https://www.infrascale.com/wp-content/plugins/super-forms/uploads/php/files/ce0da1cc6e1f4961c3805a4be6358d1f/24849952247.pdfIn PDF document text
    • https://olgapopovaphoto.com/wp-content/plugins/super-forms/uploads/php/files/597c2f5271d1cf28148e02ab27d6f572/wanepipebikajuk.pdfIn PDF document text
    • https://condicionamentofisico.com/arquivos/file/76479988078.pdfIn PDF document text
    • http://cuatro-pr.org/sites/default/files/file/8804941799.pdfIn PDF document text
    • https://rzfmuhasebe.com/userfiles/file/zuximozimuxil.pdfIn PDF document text
    • http://namjapizza.com/app/webroot/files/61004217526.pdfIn PDF document text
    • https://criteriacambio.com.br/wp-content/plugins/super-forms/uploads/php/files/c1tgk9o7auf37rjumnn2msp00p/9106971056.pdfIn PDF document text
    • https://yenhuy.vn/upload/files/jikineneje.pdfIn PDF document text
    • http://xn--d1achljw0b.xn--p1ai/content/upload/51388574965.pdfIn PDF document text
    • http://allasclub.com/campannas/file/luvaf.pdfIn PDF document text
    • https://www.brightfieldbusinesshub.co.uk/wp-content/plugins/super-forms/uploads/php/files/amt2a5bh66qh1be6ejd6clqfcb/ligolavubapipinidesoj.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=alfa+laval+separator+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_off0000c4f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC4F7 20060 bytes
SHA-256: 7afa1544720f42bbcba656f450bb639801a3865dab333c7108610c5eb72a9847
font_01_sfnt_off0000f9b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9B7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000111ce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111CE 10344 bytes
SHA-256: c595aacf175ff28228d9c5b5505961780770e095617936c862f51a97eedf8ada