Malicious PDF — malware analysis report

Static analysis result for SHA-256 20cd87d89c54586f…

MALICIOUS

PDF

72.7 KB Created: 2021-09-20 01:09:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 5c4d3b4b5ee88fbf59437e44bfe56d82 SHA-1: 45052c140e0356688b45e96f3dc9f6bfb94d4fb5 SHA-256: 20cd87d89c54586fd445dcbfba3491144260fdcc632893ba5b355ac0929b358a
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, indicating a link farm. The ML classifier strongly flagged this PDF as malicious. The presence of multiple distinct hosts and link farm characteristics suggests an attempt to manipulate search engine results or distribute malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 5

  • 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://fiumaradelsossio.it/userfiles/files/zadut.pdf In PDF document text
    • http://zzzwchem.com/upload/files/38706477767.pdfIn PDF document text
    • http://beckydavidsonhomes.com/wp-content/plugins/formcraft/file-upload/server/content/files/161422591a7a99---vetizato.pdfIn PDF document text
    • http://witnesstherealist.com/wp-content/plugins/super-forms/uploads/php/files/9250d5b898ebe7fef8f320b9acb4b333/72090555174.pdfIn PDF document text
    • http://houselandia.ru/files/30143678001.pdfIn PDF document text
    • https://choiceenergynetwork.com/wp-content/plugins/super-forms/uploads/php/files/7b86cf7bf7396fc0913c7d0f5464c7a5/80629130752.pdfIn PDF document text
    • https://pluckywize.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613711bd1578e---60282944574.pdfIn PDF document text
    • https://yam-token.com/business_school/uploads/file/20781689544.pdfIn PDF document text
    • http://dc-3ed4d7413bdb.prshots.de/uploads/userfiles/1630789972/files/38768344361.pdfIn PDF document text
    • http://avision-italia.com/userfiles/files/waxud.pdfIn PDF document text
    • http://szermgrt.hu/uploads/ckfinder/userfiles/files/befitixixinuropidaj.pdfIn PDF document text
    • https://gangnampools.com/contents/files/disegikuvaver.pdfIn PDF document text
    • http://www.thaiboat.net/image/upload/File/51053222549.pdfIn PDF document text
    • http://eastcity.hu/ufiles/file/nefixubozawitijopuliwuxo.pdfIn PDF document text
    • http://sziszolg.hu/editor_up/tegemosopebufuboramokud.pdfIn PDF document text
    • https://www.ogblfrontaliers.fr/wp-content/plugins/super-forms/uploads/php/files/adae91tn2msohrgieaqn07k51s/29274511987.pdfIn PDF document text
    • http://coyada.com/up_images/up_images/19546981545.pdfIn PDF document text
    • http://crystal-lamp.ru/uploads/files/48291683783.pdfIn PDF document text
    • http://lideparts.com/userfiles/file/1630601526.pdfIn PDF document text
    • http://jualumnitoronto.com/editor/uploadfiles/94390812913.pdfIn PDF document text
    • http://bimbrlata.cz/UserFiles/File/61320026845.pdfIn PDF document text
    • http://consol.hu/images/uploadedimages/file/89940616881.pdfIn PDF document text
    • https://corcreation.twbiz.me/data/fckeditor/files/20210914_043804.pdfIn PDF document text
    • https://gjbuyerbroker.com/userfiles/file/12857749106.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=balance+exercises+for+multiple+sclerosis+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_off0000b8fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB8FD 16588 bytes
SHA-256: 82d253a263ed43d034ae90ad0216116a96ca45aa38afa08326679615cda4257b
font_01_sfnt_off0000e362.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE362 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fb79.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB79 11036 bytes
SHA-256: e8a64fc0ce6abe988eb72ddd45f79d30491d0115b1053942e55124184538a6c6