Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8edd2a798cf7155…

MALICIOUS

PDF

30.8 KB Created: 2018-06-11 09:32:08 -04:00 Authoring application: wkhtmltopdf 0.12.4 (via Qt 4.8.7) First seen: 2020-09-04
MD5: a41a4da135fd5af4ad5e0dd9602e98f5 SHA-1: c08c3243ab1d5b377088586b1205fabdef4c1f7b SHA-256: a8edd2a798cf7155c9c2e7e94e7f6b6ffc2a444d89b467112d261591917ceae3
130 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell

The PDF document contains multiple embedded URLs, with one specifically flagged as an external URI pointing to a PHP script. The document body text, though partially garbled, suggests a lure related to 'solutions manual for probability and statistics', and the presence of a 'download button' heuristic further supports a malicious download attempt. The ML classifier also flagged this PDF as malicious with high confidence. No scripts were extracted, limiting the ability to determine the exact payload or execution method.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9648

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=solutions-manual-for-probability-and-statistics-degroot.pdf In PDF document text
    • http://uncpbisdegree.com/download4.php?q=solutions-manual-for-probability-and-statistics-degroot.pdfIn PDF document text
    • http://www.spxprecision.com/solutions-manual-degroot-probability-and-statistics.pdfIn PDF document text
    • http://www.slader.com/textbook/9780321500465-probability-and-statistics-4th-edition/In PDF document text
    • http://www.econterms.com/econtent.htmlIn PDF document text
    • http://www.asalchat.tv/In PDF document text
    • http://www.browardsheriffsoffice.org/In PDF document text
    • http://p30download.com/fa/entry/48052/In PDF document text
    • http://www.positivedisintegration.com/positivepsychology.htmIn PDF document text
    • http://www.lextutor.ca/freq/lists_download/brown_freq.xlsIn PDF document text
    • http://riverside-resort.net/1/winter-dreams-question-answer-key.pdfIn PDF document text
    • http://riverside-resort.net/1/viper-4204-remote-start-manual.pdfIn PDF document text
    • http://riverside-resort.net/1/zambian-sylabus-ecz-exammination-question-papers.pdfIn PDF document text
    • http://riverside-resort.net/1/when-champagne-became-french-wine-and-the-making-of-a-national-identity.pdfIn PDF document text
    • http://uncpbisdegree.com/1/staffing-agencies-workforce-solutions-by-kelly-services.pdfIn PDF document text
    • http://riverside-resort.net/1/writing-program-administration.pdfIn PDF document text
    • http://uncpbisdegree.com/1/the-american-pageant-13th-edition-guidebook-answers-key.pdfIn PDF document text
    • http://uncpbisdegree.com/1/sony-vgn-fw148j-laptops-owners-manual.pdfIn PDF document text
    • http://uncpbisdegree.com/1/the-complete-letters-of-oscar-wilde.pdfIn PDF document text
    • http://riverside-resort.net/1/white-105-tractor-shop-manual.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.chegg.com/homework-help/determine-mode-gamma-distribution-parameters-chapter-5.7-problem-4e-solution-9780321500465-excIn PDF document text
    • http://mlg.eng.cam.ac.uk/pub/topics/In PDF document text
    • https://view.officeapps.live.com/op/view.aspx?src=http%3A%2F%2Fwww.lextutor.ca%2Ffreq%2Flists_download%2Fbrown_freq.xlsIn 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_off00003c0d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x3C0D 10712 bytes
SHA-256: 10b033398b29239ad79949279caa6d667bcc4a7c0c8a9c66078928be3b75ac6f
font_01_sfnt_off00005e0b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5E0B 7408 bytes
SHA-256: 90b43524ee0dea182e8efc9fc266b0115606b7139ae904d51940d9a1f40702bb