Malicious PDF — malware analysis report

Static analysis result for SHA-256 da8fb7c48bad956b…

MALICIOUS

PDF

76.7 KB Created: 2021-09-24 05:51:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: ba65fb5e801e286da2b1b7d8b9cf15a3 SHA-1: 46ea721fb094e9c03365db395bbf4df162173846 SHA-256: da8fb7c48bad956b867e3db79fbe0bb1d6980c9e334871acf270a7a6b27443f4
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 compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the heuristic firings confirm the presence of external URI links and a link farm pattern. No scripts were extracted from this sample, but the overall structure suggests a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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 https://crysiq.ru/uplcv?utm_term=how+to+see+other+files+on+android PDF link annotation
    • http://maidichike.com/upload/files/72617782141.pdfIn PDF document text
    • http://educasters.co/ckfinder/userfiles/files/jiforubir.pdfIn PDF document text
    • http://geodez.com/pliki/file/noganodeloda.pdfIn PDF document text
    • https://ag-concept.ru/wp-content/plugins/super-forms/uploads/php/files/8c3f28ad24f4d857a8fbbfa1b238365f/ruwatekiw.pdfIn PDF document text
    • http://sinoorchids.com/image/file/zexepopufimirewikiwapada.pdfIn PDF document text
    • http://computer-rudolstadt.de/upload/file/mizugolodaf.pdfIn PDF document text
    • https://adurucui.com/ckfinder/files/28196883519.pdfIn PDF document text
    • https://cmf8.ir/data/file/549693060.pdfIn PDF document text
    • http://assessmentinsight.com/ckfinder/userfiles/files/xogumegukuzarikupevebe.pdfIn PDF document text
    • http://cee1968.com/ckfinder/userfiles/files/59378442327.pdfIn PDF document text
    • http://studioagronomoserragiotto.eu/userfiles/files/80735641742.pdfIn PDF document text
    • http://sb555.com/photo/file/zudosetefi.pdfIn PDF document text
    • http://niktid.ru/userfiles/file/42499689950.pdfIn PDF document text
    • http://www.solarwindependence.com/ckfinder/userfiles/files/37757974977.pdfIn PDF document text
    • https://beautyyaurient.com/editor_upload/file/33637606680.pdfIn PDF document text
    • http://wbbray.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613530671a36f---31118502675.pdfIn PDF document text
    • http://huspanda.com/data/ckfinder/files/zirakemagi.pdfIn PDF document text
    • http://thietbimaugiao.vn/Images_upload/files/fopuwus.pdfIn PDF document text
    • https://tch.lu/files/files/72747132265.pdfIn PDF document text
    • http://droprint.my/home/ququ4923/public_html/userfiles/file/6907557169.pdfIn PDF document text
    • https://www.bevillelecomte.com/ckfinder/userfiles/files/fezurupowesapedibu.pdfIn PDF document text
    • https://nffcd.org/userfiles/files/wezozavovobitusika.pdfIn PDF document text
    • https://glosunspa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f265dc46a4---1653623621.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_off0000c867.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC867 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e07e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE07E 10528 bytes
SHA-256: 08130d14e921e3cd00a8e6922f83fe93f7ff919f6626f9e0653fb093ad5d0ba5
font_02_sfnt_off0000f865.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF865 17304 bytes
SHA-256: 7f2aafa832b662d0f2ff38a4b010a06c48010eb630855670bfc7e71ae3720261