Malicious PDF — malware analysis report

Static analysis result for SHA-256 cbffc5f0beb76df6…

MALICIOUS

PDF

82.7 KB Created: 2021-09-02 21:25:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: c5052e7186aa303648570addfcdcff94 SHA-1: 977ffb19ea5b3ae50b96d6a37ca8917a6ffaf763 SHA-256: cbffc5f0beb76df67295f062b6050a7762dd162ecc9861e12ca81cae479a64f6
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external URIs, many of which point to compromised WordPress sites or disposable hosting, suggesting a phishing or malware distribution scheme. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to download a second-stage payload via the embedded links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 8

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://laborke.ru/uplcv?utm_term=best+free+pdf+writer+for+windows+xp PDF link annotation
    • https://alibabaoman.com/basefile/alibabaomancom/files/97229577156.pdfIn PDF document text
    • https://luxm.pl/userfiles/file/nijisudu.pdfIn PDF document text
    • https://gs-hemeringen.de/ablage/userfiles/files/pafisofusezejupiwikar.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ec4e1854d86---bewuxevofedupowade.pdfIn PDF document text
    • http://adria-ex.com/images/blog//file/fefibujejuzulifaxalebas.pdfIn PDF document text
    • https://evg-prague.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160a1d57f54a5e---49579763105.pdfIn PDF document text
    • http://andreagarciam.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a1eef06aa9a---getefafiwoxivugawufowe.pdfIn PDF document text
    • http://gorisum.net/fckeditor/upload_file/file/39091537353.pdfIn PDF document text
    • https://frontiersneurophotonics.org/wp-content/plugins/formcraft/file-upload/server/content/files/1/16087384389a7a---66878013398.pdfIn PDF document text
    • https://warungmimpishio2.com/contents//files/vakuponaj.pdfIn PDF document text
    • https://www.siemers-deutschmann.de/wp-content/plugins/super-forms/uploads/php/files/ft59ho7ttpeveaav0imdnvc6bi/mokikukiguminokonuxiso.pdfIn PDF document text
    • http://chiangmai-esc.net/user_img/files/7567975723.pdfIn PDF document text
    • https://bozoklar.org/ckfinder/userfiles/files/voraxobetag.pdfIn PDF document text
    • https://gertiesbloomers.com/kousumi/nulook/upload/fckimages/file/19400594501.pdfIn PDF document text
    • http://cravaluos.com/ckfinder/userfiles/files/40022113953.pdfIn PDF document text
    • http://quadocdao.vn/uploads/files/39264833504.pdfIn PDF document text
    • http://informerfitness.com/wp-content/plugins/super-forms/uploads/php/files/1bf453161bf3edf765274525b8eda898/78380056661.pdfIn PDF document text
    • http://klimagra.pl/images/wysiwyg_img/file/diwedobarap.pdfIn PDF document text
    • https://agri-mal.pl/userfiles/file/32184020078.pdfIn PDF document text
    • https://kalatranslation.co.uk/wp-content/plugins/super-forms/uploads/php/files/of6ckqjan9bn6os6bhq613tkfq/begizonaz.pdfIn PDF document text
    • http://toyotaprius-custom.com/js/upload/files/54239105650.pdfIn PDF document text
    • http://tecumseh1962.com/clients/85183/File/beparegovumevovakekibe.pdfIn PDF document text
    • https://earplighting.com/wp-content/plugins/super-forms/uploads/php/files/fee3cea99fc37ea04f682aa0d83c39f5/jazejo.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_off0000dca6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCA6 10524 bytes
SHA-256: aa2499d93bbd42153bb939fc87119aaae8682214de8cea4954c7e4f1614c32d5
font_01_sfnt_off0000f4cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4CB 18752 bytes
SHA-256: 495dcd1b0a95a7bc28e33be34d69d863d6ddcddf8ed15ec368b534c020ea8c22
font_02_sfnt_off00012533.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12533 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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