Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf254a19b08305fc…

MALICIOUS

PDF

81.9 KB Created: 2021-08-21 21:00:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 5726eb15d69bef07994915c9d71542bf SHA-1: 85529e431963d90a00f8d993d5f77324b3c97f29 SHA-256: cf254a19b08305fc553ca060b66fe54e8b8d1d8aa99bc142ab4eb7863e0f04b3
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised WordPress upload storage or disposable hosting, suggesting a link farm or phishing lure. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this. No scripts were extracted, but the PDF structure itself is used to host these malicious 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://crysiq.ru/uplcv?utm_term=ielts+exam+past+questions+and+answers PDF link annotation
    • https://tckontrola.hr/files/tilurudataberuzokemimi.pdfIn PDF document text
    • http://miamiwars.pl/wp-content/plugins/super-forms/uploads/php/files/131bbc946ee6fa0fcd24741c9d209044/rokufezigitofeji.pdfIn PDF document text
    • https://duproject.com/uploadEditor/files/30611336191.pdfIn PDF document text
    • https://homestayhoian.vn/uploads/image/files/jitesevatadekosovupu.pdfIn PDF document text
    • http://tchid.net/userfiles/file/lezejafefib.pdfIn PDF document text
    • https://kaptenhoki.com/contents//files/besev.pdfIn PDF document text
    • http://marty-triple-m.ch/inhalt/files/juxidelivitenod.pdfIn PDF document text
    • https://accesoriosalmayor.com/images/userfiles/file/12580848777.pdfIn PDF document text
    • http://ykzn8.com/upfiles/editor/files/54320850034.pdfIn PDF document text
    • http://airconbank.com/upload/fckeditor/file/bawaxutani.pdfIn PDF document text
    • http://www.huntsvillepr.com/files/files/sijija.pdfIn PDF document text
    • http://mayingiabao.com/upload/files/5760863126.pdfIn PDF document text
    • https://nucamsa.es/userfiles/files/sekojiwuxugupufizemexuze.pdfIn PDF document text
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/9b9059b2fabb27736de9a2217b38df10/rejefunawoxoxivudobimupo.pdfIn PDF document text
    • http://zhodnoceni-penez.cz/is/images/FCKeditor/File/8126269354.pdfIn PDF document text
    • http://kolaykanal.com/userfiles/files/wejopuz.pdfIn PDF document text
    • http://artkulinaria.pl/sites/default/files/file/pezuzorumikusebibijukefe.pdfIn PDF document text
    • http://amwordpress.org/wp-content/plugins/formcraft/file-upload/server/content/files/160760592b64d9---govukifoxapawa.pdfIn PDF document text
    • https://weinquartier.at/wp-content/plugins/super-forms/uploads/php/files/7a8782deb42aad11c25528dda3255283/somanisolo.pdfIn PDF document text
    • http://www.kreasoft.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1606f71cb1e4e7---27450053267.pdfIn PDF document text
    • http://clear-es.net/yamituki-n/uploads/files/xepafoluwuvamu.pdfIn PDF document text
    • https://directorvincentchow.com/fck_filemanager_upload/file/75946733218.pdfIn PDF document text
    • http://ddgasul.com/userfiles/file/papula.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_off0000de62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE62 16096 bytes
SHA-256: 2c4dff5ca0e7ef37ce3666d36e94c0d9ee43a1236327d8013398d8d0873b6927
font_01_sfnt_off000107a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107A8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011fbf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FBF 10936 bytes
SHA-256: 2549b64d714c2769708ed64cc3a36e5347b0431b95ed2460a759157d33ca1d3a

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