Malicious PDF — malware analysis report

Static analysis result for SHA-256 880fe8676b96cc7b…

MALICIOUS

PDF

70.3 KB Created: 2021-09-26 09:16:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 201c031965b84a2488a6dee03a862f3d SHA-1: 752fe9f3515127ff891ab01d587d8ce09f1011e9 SHA-256: 880fe8676b96cc7b04fdb0062c645014f29b93044139f2bf57bdb02f47c544ff
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous embedded URLs that point to other PDF files hosted on compromised CMS uploads and disposable domains, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the heuristic firings suggest it is part of a link farm strategy. No scripts were extracted from this sample.

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 https://pistant.ru/uplcv?utm_term=video+compressor+video+converter+apk PDF link annotation
    • https://2b3la571ga-70p.com/contents/files/kejezisa.pdfIn PDF document text
    • https://sunkamalzemecilik.com/userfiles/file/79477876497.pdfIn PDF document text
    • https://storage-in-motion.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614ffc4b6eb00---88691175686.pdfIn PDF document text
    • http://gocchame.vn/app/webroot/img/uploads/files/43689235699.pdfIn PDF document text
    • http://stkvn.ru/wp-content/plugins/super-forms/uploads/php/files/c023b698c4a84408d879f4dd72aafa6b/72592899061.pdfIn PDF document text
    • https://www.inter-tube.co.uk/wp-content/plugins/super-forms/uploads/php/files/5510f536488c71ee123f93fb89409aae/7192361595.pdfIn PDF document text
    • https://cortemadera.com/wysiwygfiles/file/48168435139.pdfIn PDF document text
    • http://evolutionchonburi.com/userfiles/files/tosuwogurabarulafoxag.pdfIn PDF document text
    • http://kaymccarthy.com/immagini/file/58542158366.pdfIn PDF document text
    • http://myconnect-thailand.com/image/upload/File/19200790879.pdfIn PDF document text
    • https://brusroom.com/wp-content/plugins/super-forms/uploads/php/files/b03219a2e4c97d2beb64938423cc9f26/dutapaxokinotonodizozusup.pdfIn PDF document text
    • http://cathugo-catamarans.de/res/wysiwyg/file/95917642112.pdfIn PDF document text
    • https://perfectsextherapy.com/public_html/userfiles/file/10079463002.pdfIn PDF document text
    • http://www.c-l-r-p.com/admin/ckfinder/userfiles/files/22364081237.pdfIn PDF document text
    • http://prvugkh.ru/uploads/files/33582866892.pdfIn PDF document text
    • http://bangladeshceramicsociety.com/uploads/editor/files/tudifetotakerajezakezun.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131bad21cc7b---93406029116.pdfIn PDF document text
    • http://nwhouse.ru/uploads/file/nizafifonugu.pdfIn PDF document text
    • http://yaan121.com/uploads/files/202109191154086862.pdfIn PDF document text
    • http://simonide.org/userfiles/file/95421375483.pdfIn PDF document text
    • http://evolution-dev.com/file_media/file_image/file/jakexaxifur.pdfIn PDF document text
    • https://www.saltriot.com/wp-content/plugins/super-forms/uploads/php/files/4a89bf241c8b496a8f92fbf46007cedf/fejetevabajozamozox.pdfIn PDF document text
    • https://hocaukhudothithanhphogiaoluu.com/asset/site/files/77709397871.pdfIn PDF document text
    • http://zjleiou.com/images/upload/File/90819965394.pdfIn PDF document text
    • 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_off0000b0fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB0FC 10756 bytes
SHA-256: d5dd243ef6e732b98c5e7713b8f1fb3af643769800e1d04b622df216ad5b3c80
font_01_sfnt_off0000c9b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9B5 16636 bytes
SHA-256: f49e6251ffcf565ef3346e0ad3706c8bd65f84359b88db406576b0a3ed2904fa
font_02_sfnt_off0000f3df.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3DF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1