Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8936401e428b607…

MALICIOUS

PDF

72.7 KB Created: 2021-10-04 03:19:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 674270da67a400392e4b29b3275fa7e2 SHA-1: 71ec27741672a49ae9c0091dd8190398e470dc06 SHA-256: b8936401e428b607be942a8dc81d7eeaffbbf53450393ff4e703a673ab47c0ae
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external URIs, many of which are hosted on compromised WordPress sites or disposable domains, indicating a link farm or redirection scheme. The ML classifier strongly flagged this PDF as malicious, supporting the hypothesis that it is used to direct users to potentially harmful content or further stages of an attack. The presence of embedded JavaScript suggests an attempt to execute code within the user's browser or PDF reader.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 6

  • 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.
  • 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 http://korvet-sp.ru/userfiles/file/jagulumipusaxomosa.pdf In PDF document text
    • https://ddnepal.com/assets/userfiles/files/41783163211.pdfIn PDF document text
    • http://orderkai.com/uploads/files/44903299260.pdfIn PDF document text
    • http://ebbers-schilderwerken.nl/uploads/files/83945825669.pdfIn PDF document text
    • http://playitdirect.ca/ckfinder/uploadfiles/files/98075739951.pdfIn PDF document text
    • http://sgrdinstitutionspandher.org/sgrd/userfiles/file/korarujo.pdfIn PDF document text
    • http://corse.annuaire-regional.com/ckfinder/userfiles/files/37080568164.pdfIn PDF document text
    • http://deleeuwputten.nl/site/data/ws/files/58562845595.pdfIn PDF document text
    • http://sochi-polyana.com/ckfinder/userfiles/files/gipasale.pdfIn PDF document text
    • https://www.webhisto.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1615a10e60ecf6---73196309197.pdfIn PDF document text
    • https://rentcar888.com/uploads/files/202109190746317916.pdfIn PDF document text
    • http://eschool365.in/js/admin/uploadfiles/file/nejezanusojawetirune.pdfIn PDF document text
    • http://phdpecs.hu/userfiles/files/53018946243.pdfIn PDF document text
    • http://bkht.vn/userfiles/file/pafemiwa.pdfIn PDF document text
    • http://www.superior-inkjet.com/login/ckfinder/userfiles/files/silaxakumexuzipatiwa.pdfIn PDF document text
    • https://cornwallstaffagency.com/userfiles/file/68471134451.pdfIn PDF document text
    • http://badgerhillfarm.uk/46681794360.pdfIn PDF document text
    • http://cn-junsheng.com/upload/file///202191975630575.pdfIn PDF document text
    • http://forma8.kz/ckfinder/userfiles/files/zuvulozopamowukopenuxula.pdfIn PDF document text
    • http://gdgom.com/upload/file/2109180154286742519e0isjb01cvt.pdfIn PDF document text
    • http://www.champcaregivers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16155cf63a79b7---17773873752.pdfIn PDF document text
    • http://law885995.com/upload/fckimages/file/27352233151.pdfIn PDF document text
    • https://www.lumisolar.pe/wp-content/plugins/formcraft/file-upload/server/content/files/161581320ae075---jedofuked.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=mr+lonely+tylerPDF 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_off0000b65d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB65D 9788 bytes
SHA-256: ce078bf83b0e780ff5e3e5a6b4cf528ff54989e9bcf57fabba9c4350dd307476
font_01_sfnt_off0000cbed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBED 18952 bytes
SHA-256: dcd737b215a853052ac164a89da2af12d6a813baaa69ca04904e05b80a88e5c7
font_02_sfnt_off0000fd8c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD8C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1