Malicious PDF — malware analysis report

Static analysis result for SHA-256 4bf491b9ce6ec9b6…

MALICIOUS

PDF

69.8 KB Created: 2021-09-25 18:58:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 0c9b39c282eaa2e8f1f04fe9d935f3ec SHA-1: cc2e4f263ba61d3ed4dffb4574fea8f0b6ab3cd6 SHA-256: 4bf491b9ce6ec9b6cbc0ef8a8ab9fb306e71ac14bc0817950f68a7dd8ceb345d
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, many pointing to disposable hosting, suggesting a link farm or phishing lure. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM specifically indicates a non-clustered link farm on disposable hosting, and the presence of external URIs further supports this. While no scripts were explicitly extracted, the nature of the embedded links and the ML detection suggest an attempt to redirect users to malicious content, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://laborke.ru/uplcv?utm_term=ps1+download+apk PDF link annotation
    • https://fallsplat.se/bildbank/file/rixabe.pdfIn PDF document text
    • http://www.coverseg.com/uploads/ckfinder/files/zopetimunolu.pdfIn PDF document text
    • http://aurastaffing.es/upload/file/33229480306.pdfIn PDF document text
    • https://sogelec-eng.com/files/ckfinder/files/39586892536.pdfIn PDF document text
    • http://3bbb.fr/ckeditor/upload/files/74495790154.pdfIn PDF document text
    • https://nk-sostanj.si/files/file/jinanowewofuvibudisidigok.pdfIn PDF document text
    • http://strelnicebudejovice.cz/userfiles/file/24812232465.pdfIn PDF document text
    • https://aurorabersinar2.com/contents/files/96985108577.pdfIn PDF document text
    • http://hoilhpnqbthanh.com/upload/file/musarixagikisubexarole.pdfIn PDF document text
    • https://ijmscr.com/ckfinder/userfiles/files/xogugudepajuwenetiz.pdfIn PDF document text
    • https://tpk-m.ru/files/file/254445022.pdfIn PDF document text
    • http://www.realisthotel.com/wp-content/plugins/formcraft/file-upload/server/content/files/161357dbb0f29d---gifezigewafipinup.pdfIn PDF document text
    • https://noventa.cz/media/files/file/12981950911.pdfIn PDF document text
    • http://jcpingie.be/public/files/86869433831.pdfIn PDF document text
    • https://gestionarival.com/userfiles/file/23861235677.pdfIn PDF document text
    • https://kaptenhoki.com/contents/files/7973268712.pdfIn PDF document text
    • http://sanalights.com/admin/admin/uploadfiles/file/24854131833.pdfIn PDF document text
    • http://vindindex.nl/images/uploads/siguwifovojeje.pdfIn PDF document text
    • https://aimhc.com/userfiles/file/gijaraxebinel.pdfIn PDF document text
    • http://www.ponderosafestival.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140dbb9c4d4a---nemikotonunaxazugat.pdfIn PDF document text
    • http://woori-tour.kr/FileData/ckfinder/files/20210906_DCC1B63305C49A58.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_off0000adab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xADAB 17536 bytes
SHA-256: 391cbb59c97437c7eaa7250d9bb922080acedd9e5f8da847af15a6cdd345c461
font_01_sfnt_off0000dae9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAE9 10192 bytes
SHA-256: 18533f0b456b8b528f3cb82a1b0210171e74b9daf10dc2b1387ab6f24bd9c9a1
font_02_sfnt_off0000f1fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1FB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1