Malicious PDF — malware analysis report

Static analysis result for SHA-256 da546a7fa9941daa…

MALICIOUS

PDF

81.2 KB Created: 2021-09-11 02:18:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: a5bbbc2c2488de0a51aceb925b34ffe7 SHA-1: 24e1d10d214ed36d1fe20a7d146e086afdd4d4d1 SHA-256: da546a7fa9941daa3b24f9208eda28824ce6f71995e2757373d08be795ac3b25
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to other PDF files hosted on various domains. Several heuristics indicate this is a link farm, with one specifically identifying a link to a compromised WordPress upload directory. The ML classifier strongly flagged this PDF as malicious, suggesting it's part of a distribution or SEO manipulation scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://jyjwqj.com/uploadfile/file///2021090904090687.pdf In PDF document text
    • http://xy-interior.com/uploads/files/202109011956537253.pdfIn PDF document text
    • https://transilvaniafishing.ro/app/webroot/files/userfiles/files/mezosufoxidiposar.pdfIn PDF document text
    • http://lirealestatelitigator.com/wp-content/plugins/super-forms/uploads/php/files/3d16fc9e901f12ace0f5d1c8e9ee5009/54501260284.pdfIn PDF document text
    • https://k31szmq42-nu28.com/contents/files/jutuval.pdfIn PDF document text
    • https://magnettoptan.com/upload/ckfinder/files/19630286932.pdfIn PDF document text
    • http://baanpowertrain.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612e9888c257b---piwimow.pdfIn PDF document text
    • http://golfvillageonline.com/userfiles/file/62870883148.pdfIn PDF document text
    • https://lapalettedesarts.fr/gestion/file/batovini.pdfIn PDF document text
    • http://greenearthgardens.org/userfiles/10358680012.pdfIn PDF document text
    • https://revive.fashion/upload/files/fuxigo.pdfIn PDF document text
    • http://jiangsutravel.kr/userfiles/files/20210911_063031.pdfIn PDF document text
    • https://intervalhousehamilton.org/ckfinder/userfiles/files/godakifujabedugevetu.pdfIn PDF document text
    • http://phulieumaymacbaoco.com/hinhanh_fckeditor/file/3617985741.pdfIn PDF document text
    • http://vandientuchinhhang.com/upload/files/48495097897.pdfIn PDF document text
    • http://pulsrmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b8becba3a7---74243786481.pdfIn PDF document text
    • http://mega.kz/media/upload/files/51084238365.pdfIn PDF document text
    • https://treasurehunterdetectors.com/ckfinder/userfiles/files/53807152400.pdfIn PDF document text
    • https://quangcaowebsite.vn/uploads/files/52181616393.pdfIn PDF document text
    • https://htijsr.com/userfiles/file/30883401515.pdfIn PDF document text
    • https://poldercuptrofee.nl/site/admin/ckfinder/userfilesfiles/26240825794.pdfIn PDF document text
    • https://ideylia.fr/uploads/file/41856522035.pdfIn PDF document text
    • http://cottoneauto.it/userfiles/files/10779101721.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=can+you+buy+ringtones+for+androidPDF link annotation
    • https://forums.androidcentral.com/showthread.php?t=526298&s=9638a4f8D8e386df05a3fb97e724a3fb97e7e724In 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
    • https://forums.androidcentral.com/showthread.php?t=526298&s=9638a4f8D8e386df05a3fb97e724a3fb97e7e724In 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_off0000d6ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6FF 10868 bytes
SHA-256: 8395e437fa305e3819642fe67a71c72fe3c1e1f69e238b53607926f9f3f0b3ee
font_01_sfnt_off0000f01b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF01B 18116 bytes
SHA-256: dfab7f8ff697b04ad3f573a46b6c2c4d7930ba535036fe590c32d1c66bcb580f
font_02_sfnt_off00011eeb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EEB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1