Malicious PDF — malware analysis report

Static analysis result for SHA-256 641b64403c9e0c3c…

MALICIOUS

PDF

86.6 KB Created: 2021-08-10 10:24:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: cfc40e4f44691d2186695cf13050428c SHA-1: b9a4037278c95ea9757a85258f70608da7f5f18f SHA-256: 641b64403c9e0c3c28181e363a0cd0a8fb0283189d764e3e7ccd45e0076fe6ed
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links to other PDF files hosted on compromised websites, indicating a link farm or distribution mechanism. The ClamAV detection and ML classifier strongly suggest malicious intent, likely related to phishing or malware distribution. No scripts were extracted, and the document body was unreadable, so the primary evidence comes from the URL heuristics and the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://jclifeschools.org/wp-content/plugins/super-forms/uploads/php/files/a931c383e7b4dc7298e170feb24207a7/tixoromoluwopetak.pdf In PDF document text
    • http://windcampus.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2eb793541e---94190843421.pdfIn PDF document text
    • https://ville-rouillac.fr/docs/file/zapedol.pdfIn PDF document text
    • http://anhuizpyy.com/upload_fck/file/2021-4-29/20210429075028815974.pdfIn PDF document text
    • http://www.fsnn.se/wp-content/plugins/formcraft/file-upload/server/content/files/160aac0b8bd2e0---jaxiso.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/98e0149cc79df7e994c12b277f5769b9/pufipezitolidofat.pdfIn PDF document text
    • https://hogies.com/includes/template/uploads/file/7306159851.pdfIn PDF document text
    • http://maynenkhiinverter.com/media/ftp/file/rujexom.pdfIn PDF document text
    • http://www.training4thefuture.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16081423096d49---4442668736.pdfIn PDF document text
    • http://richmore.kr/uploadfile/fckeditor/file/revij.pdfIn PDF document text
    • https://albawadiroad.com/userfiles/files/jirawiwofa.pdfIn PDF document text
    • http://www.auditsi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c772fd1c908---werexi.pdfIn PDF document text
    • https://drlanda.hu/user/file/lilulemamexiruxokobe.pdfIn PDF document text
    • http://skikk.eu/app/webroot/files/userfiles/files/zuxofinibofavoli.pdfIn PDF document text
    • http://arcadia6465.com/clients/f/fc/fcac8d81e62e7f23ed02b02243def538/File/siben.pdfIn PDF document text
    • http://lushexperiences.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c995243633---vojokedobanifijubemebewa.pdfIn PDF document text
    • https://cashofferoregon.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a0cffc7690f---13513389648.pdfIn PDF document text
    • http://plafondchauffant.fr//img/user/file/kitogizebe.pdfIn PDF document text
    • http://mijneigenlift.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a92ad13861f---48224245960.pdfIn PDF document text
    • http://zespolbahamas.pl/zdjecia/file/76054115784.pdfIn PDF document text
    • http://nieruchomosci-swidnica.pl/userfiles/file/bavine.pdfIn PDF document text
    • https://www.sevgiliyevideo.net/wp-content/plugins/formcraft/file-upload/server/content/files/160a4481ae6033---vuvepoginobogesilevutovag.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=dividing+whole+numbers+by+unit+fractions+worksheet+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_off0000eb1b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB1B 16992 bytes
SHA-256: ca48abf797588c2c9de4fbcac8a9b8556e26ca0f22a0c09a5bae8b70fde06a92
font_01_sfnt_off00011779.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11779 11664 bytes
SHA-256: 65755858cba3fcc933d76fed3f10dcce93102d8d2d42811152254b6560a6c83e
font_02_sfnt_off000132b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x132B5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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