Malicious PDF — malware analysis report

Static analysis result for SHA-256 331c8658abf54b14…

MALICIOUS

PDF

81.9 KB Created: 2021-06-30 01:29:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e5a4fcc41b48001cdd8c3a30401b0e6a SHA-1: baa044b91a540e8f7fef027abf6075df6e05ef04 SHA-256: 331c8658abf54b1425262ec9bd7aae51d653e8b7d3c2fc7cbc1b708e60612991
156 Risk Score

Malware Insights

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

The PDF contains a large number of links, many of which point to compromised WordPress sites. The 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' heuristics indicate this is a link farm designed to leverage compromised infrastructure. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution through these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/1609b98bd4cdf1---29847049868.pdf
    • https://noks.cz/wp-content/plugins/formcraft/file-upload/server/content/files/160a4cb46355cb---sufojuradim.pdf
    • http://vipnjl.com/userfiles/files/91249307287.pdf
    • http://www.jcca.co.in/wp-content/plugins/formcraft/file-upload/server/content/files/160c21fc0c2912---zogupuva.pdf
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/16079133d76a7d---buxigovibewokutuzofiku.pdf
    • https://kaptenhoki.net/contents//files/firakarub.pdf
    • https://uaqbakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0c6a9cd16a---mubesudejiwekodokikozeka.pdf
    • http://projectbudapest.hu/wp-content/plugins/formcraft/file-upload/server/content/files/160862a2c30d20---12137484218.pdf
    • https://jfefood.com/wp-content/plugins/super-forms/uploads/php/files/ff6c07b74b422d2ad8f93cf604b09895/rolusuvudisunigo.pdf
    • https://finestblogger.de/wp-content/plugins/super-forms/uploads/php/files/l91dv45dviq07u1q8da1q1sgh9/nadivutenopami.pdf
    • https://decoveinvestment.com/userfiles/file/bufonogine.pdf
    • https://alzubidi.com/userfiles/files/filuvewufidunakubej.pdf
    • http://johncarroll1967.com/clients/1/18/1896e795ecc2602204d707ec4e69586f/File/muvuforamozukesifezakigop.pdf
    • http://tdfinalists.ca/clients/43449/File/xixujezezoxibovonep.pdf
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/84cdbvhte91hei30g10blvfpum/65118240347.pdf
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160901eb3c1f22---29594638280.pdf
    • https://www.karavanlakesfet.com/wp-content/plugins/super-forms/uploads/php/files/92a623788c6b50a2158d4c97144d88fa/situmewatixuvebejod.pdf
    • https://haps.company/wp-content/plugins/super-forms/uploads/php/files/g0aai6formhvp9druqibmibji1/39503150585.pdf
    • http://piazzademarini3ge.com/userfiles/files/84682440195.pdf
    • http://www.mondzorgvesa-voorschoten.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160cc76723e922---39106362028.pdf
    • https://www.masismarketing.com/wp-content/plugins/super-forms/uploads/php/files/ae18bf50a44c91df2869bbb7438977ea/75647714605.pdf
    • https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/rinmhjks0bpcabic75qqjpbirk/14133578050.pdf
    • https://www.llgnjinc.com/wp-content/plugins/super-forms/uploads/php/files/d0f06c7cb90893e58b005a75051259fb/dipebemarirunasazaw.pdf
    • https://www.asahinafunnels.com/wp-content/plugins/super-forms/uploads/php/files/001u1ofevdreqrirlt3nipnjau/loxaxujew.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=file+names+from+folder+to+excel
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dd8b.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDD8B 16792 bytes
font_01_sfnt_off0000f59d.bin
9f7ed5d99307197a219159579cb45cb25ebd28d11d66395ca7aa46e1b846cbcd
pdf-font-stream PDF embedded font (sfnt) at offset 0xF59D 16884 bytes
font_02_sfnt_off000121e4.bin
dc8cd2a9bc8a6fe4f8b39630f23263fccb308f7a881305d8b4e0fdb2bea0c352
pdf-font-stream PDF embedded font (sfnt) at offset 0x121E4 10716 bytes