Malicious PDF — malware analysis report

Static analysis result for SHA-256 7a8c51049854a539…

MALICIOUS

PDF

84.6 KB Created: 2021-09-06 16:53:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: f4279ea215f44cdb614d92f1377edc7c SHA-1: 72e16c5a984f8ad2d42132b2a857527b917b1f91 SHA-256: 7a8c51049854a5391408b1f9b0395a2e31688caae61d55c9f664301fd74b308f
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to compromised WordPress sites or disposable hosting, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely involving exploitation of PDF vulnerabilities to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://krisoc.ru/uplcv?utm_term=pythagorean+worksheets+free PDF link annotation
    • http://bjdfszwy.com/filespath/files/20210813111900.pdfIn PDF document text
    • https://proff-doors.ru/wp-content/plugins/super-forms/uploads/php/files/3fb709f516e8bc0f72afee71a2490a9f/ratuxo.pdfIn PDF document text
    • https://www.audifonosdoshoydos.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d45bcb3f33---42883262055.pdfIn PDF document text
    • http://bon-mar.com/fck_user_files/file/fimerigawinut.pdfIn PDF document text
    • http://yao-cheng.com/uploadfiles/20210729194721.pdfIn PDF document text
    • https://lion-trading.co.uk/wp-content/plugins/super-forms/uploads/php/files/3l7tkapq8eqec0eqgbgu7fa8ao/15542841472.pdfIn PDF document text
    • https://edoxmarketing.com/wp-content/plugins/super-forms/uploads/php/files/rgqun5lmtus8pcne8q6enn92s8/zasikagurewubufonime.pdfIn PDF document text
    • https://www.grecosalesinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2d27a940c4---vufavesasopos.pdfIn PDF document text
    • http://www.apsetedavisi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072866275c14---lixulepuma.pdfIn PDF document text
    • http://www.garriagricola.com/wp-content/plugins/formcraft/file-upload/server/content/files/160acdcf267024---11385659999.pdfIn PDF document text
    • https://www.temsilcisitesi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084589d62763---kipitiwojamuduro.pdfIn PDF document text
    • http://altelaw.com/uploads/image/file/61972605507.pdfIn PDF document text
    • http://www.x454.com/wp-content/plugins/super-forms/uploads/php/files/silfusc10to8pg4jb6evskism6/farirogaralizesovu.pdfIn PDF document text
    • http://jshtextile.com/UserFiles/file///91144098749.pdfIn PDF document text
    • http://gyorszol.hu/userfiles/file/6316212295.pdfIn PDF document text
    • http://willtorock.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071feba44c81---mapupeladuzimo.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/n0p4vfjaefi6vejd67mlg1kttg/ruzed.pdfIn PDF document text
    • http://pratiklinik.com/img/userfiles/files/47078093758.pdfIn PDF document text
    • http://muntepa.com/userfiles/files/52171051085.pdfIn PDF document text
    • https://lisacutler.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609690ae4b52b---lunasibagiguto.pdfIn PDF document text
    • http://wsp.pl/userfiles/file/lafuxibafovipawuvusolat.pdfIn PDF document text
    • http://smith-williamssisters.com/clients/d/dd/dd6cbc7353a6ef31c13ccaa63ab862ac/File/10341560455.pdfIn PDF document text
    • http://1utilaje.ro/mm/file/36056291687.pdfIn PDF document text
    • https://alarrabnews.com/images/content/content/file/15693305746.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_off0000e3ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3EE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fc05.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC05 10648 bytes
SHA-256: 56f473e0dfee77da8d8a9e8192fad31c001d164c7242da49e79476580dadef9f
font_02_sfnt_off00011480.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11480 18828 bytes
SHA-256: 78492381406fd395146ec3c9904430aeaef12c509d56db1e823b44fcc0d1bec4