Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf5876456940cb90…

MALICIOUS

PDF

28.5 KB Created: 2018-06-11 08:47:28 -04:00 Authoring application: wkhtmltopdf 0.12.4 (via Qt 4.8.7) First seen: 2020-08-25
MD5: cb2aa7ba8bccbfab520015ee6d82f12d SHA-1: b03f6ede1f8dbe8732bfc279d40fcc2f2a0a6102 SHA-256: cf5876456940cb90a76c6b7e7818310d344299e6843f4e3d29c79bd28fa00452
130 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The ML classifier flagged this PDF with high confidence. The document body contains text and links related to downloading a PDF, and a heuristic identified a visual download button lure. The primary malicious URL is http://uncpbisdegree.com/download3.php?q=varian-intermediate-microeconomics-workouts-answers.pdf, which is likely intended to deliver a malicious payload disguised as an academic document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9683

Heuristics 4

  • Fake 'free download' SEO-poisoning PDF critical PDF_SEO_FAKE_DOWNLOAD
    The ML classifier flagged this PDF AND it carries a visual download/call-to-action lure AND an off-domain server-side download-gateway link whose query string names a document payload. This three-signal conjunction is the fake-document / 'free PDF download' SEO-poisoning delivery pattern: the page is padded with benign decoy links to dilute classifier scores while funnelling the victim through the gateway to malware/scareware. Acting only on the conjunction keeps benign download-bearing PDFs from being misflagged.
  • PDF carries a PHP-gateway SEO-spam PDF link farm medium PDF_SEO_PHP_GATEWAY_LINK_FARM
    PDF contains four or more clickable links whose target is a `.php` gateway with a multi-word search-PHRASE document slug embedded after it (e.g. 'index.php?.../binary+options+trading+nz.pdf' or 'pdf.php/cialis-dosage-side-effects.pdf'). Legitimate PHP-served documents use a filename or numeric id, not a search-query phrase, so this is the generated SEO link-farm shape — pharma / binary-options / 'free download' spam that ranks for queries and routes users into payload/redirect chains. The PDF itself carries no exploit — the risk is the linked destinations.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://uncpbisdegree.com/download3.php?q=varian-intermediate-microeconomics-workouts-answers.pdf In PDF document text
    • http://uncpbisdegree.com/download4.php?q=varian-intermediate-microeconomics-workouts-answers.pdfIn PDF document text
    • http://www.americandogapparelco.com/british/british_soldiers_in_the_american_revolution_crossword.pdfIn PDF document text
    • http://www.alexmthomas.com/ma-economics/In PDF document text
    • http://riverside-resort.net/1/suzuki-samurai-owners-manual-1987.pdfIn PDF document text
    • http://riverside-resort.net/1/spanish-is-fun-1-4th-edition-answers.pdfIn PDF document text
    • http://riverside-resort.net/1/thunder-and-sunshine-riding-home-from-patagonia-around-the-world-by-bike.pdfIn PDF document text
    • http://riverside-resort.net/1/statistics-for-managers-7th-edition-solution-manual.pdfIn PDF document text
    • http://riverside-resort.net/1/std-8-2018-maneb-resuilts.pdfIn PDF document text
    • http://riverside-resort.net/1/suzuki-swift-m16a-ecu-diagram-pinout.pdfIn PDF document text
    • http://riverside-resort.net/1/theory-of-music-exams-2010-grade-5-theory-of-music-exam-papers-abrsm.pdfIn PDF document text
    • http://riverside-resort.net/1/uk-pool-draws-for-week-18.pdfIn PDF document text
    • http://riverside-resort.net/1/the-american-vision-modern-times-chapter-16-test.pdfIn PDF document text
    • http://riverside-resort.net/1/tourism-test-book-grade-10.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.loot.co.za/index/html/index3508.htmlIn PDF document text
    • http://go.microsoft.com/fwlink/?LinkId=521839&CLCID=0409In PDF document text
    • http://go.microsoft.com/fwlink/?LinkID=246338&CLCID=0409In PDF document text
    • https://go.microsoft.com/fwlink/?linkid=868922In PDF document text
    • http://go.microsoft.com/fwlink/?LinkID=286759&CLCID=409In PDF document text
    • http://go.microsoft.com/fwlink/?LinkID=617297In PDF document text
    • https://fedoraproject.org/wiki/Licensing/LiberationFontLicenseIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000034f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x34F9 10712 bytes
SHA-256: fa99f1000aadcb4a0a8befba0a17db6c66bd0eb4fd67f2434cc3cb32c8a45292
font_01_sfnt_off000056d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x56D9 6900 bytes
SHA-256: f11960aacf70fa5897db7def670aafdcd4598320fbf34132d9cfb3f530d5f485