Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f751b2f278e8c52…

MALICIOUS

PDF

73.8 KB Created: 2021-09-07 07:54:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 031dd02bdf78199db10a88dc63700c8f SHA-1: a591fbe5df9656b962d7f206cf8b5824bb337309 SHA-256: 4f751b2f278e8c525fe26c64004383cadd7f8e7df992b643638be41ba7a4344c
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous URLs pointing to compromised WordPress sites and other disposable hosting, suggesting it functions as a link farm to distribute further malicious content or phish for credentials. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://pistant.ru/uplcv?utm_term=special+right+triangles+worksheet+math+2 PDF link annotation
    • http://movesearchesuk.com/userfiles/file/nupafuvamon.pdfIn PDF document text
    • https://mannerfeltdesignteam.se/ckfinder/userfiles/files/80761015920.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c88610b7d0---kidisan.pdfIn PDF document text
    • https://www.tessilgiada.it/wp-content/plugins/formcraft/file-upload/server/content/files/160732cfb91e82---mababugiwi.pdfIn PDF document text
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160fe3d39f1b66---24358484838.pdfIn PDF document text
    • http://dekoblickfang.de/userfiles/file/97019979077.pdfIn PDF document text
    • http://fatfailogistics.com/fckeditor/files/file/dabedonijoziziwapikufupi.pdfIn PDF document text
    • https://s-serviss.lv/userfiles/file/46851912406.pdfIn PDF document text
    • http://akbmodel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e405977e59---18933077720.pdfIn PDF document text
    • http://thermocomfort.ca/userfiles/file/53791728979.pdfIn PDF document text
    • http://zonweringbelgie.be/ckfinder/userfiles/files/98414606695.pdfIn PDF document text
    • http://phukhoabacninh.com/images/files/6764456187.pdfIn PDF document text
    • https://agenciaboom.com/wp-content/plugins/super-forms/uploads/php/files/h5ha1cungovsa6uiq9l5hpdv87/45000904937.pdfIn PDF document text
    • http://supermarketdv.ru/files/file/bamiwisexe.pdfIn PDF document text
    • https://moto-trend.cz/public/files/fck/file/visekodi.pdfIn PDF document text
    • https://robertmatzuzi-massagetherapist.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160b841d27e870---87394278639.pdfIn PDF document text
    • http://elsekmont.eu/userfiles/file/22709272911.pdfIn PDF document text
    • https://www.schroedersales.com/wp-content/plugins/super-forms/uploads/php/files/5741f95a1e3878b5380a7ff38bda5da7/14611804092.pdfIn PDF document text
    • http://a-kamen.com/userfiles/file/buzubivemulexogabo.pdfIn PDF document text
    • http://vizesblokk.hu/files/file/29705169537.pdfIn PDF document text
    • http://newgrids.com/userfiles/file/53159977602.pdfIn PDF document text
    • http://cmepta.com/clients/7/74/74ea2f63c40943e6497cbf70acaf7c81/File/77143067317.pdfIn PDF document text
    • http://195exim.com/datas/files/39016537824.pdfIn PDF document text
    • https://transpack-krumbach.de/_upload_bilder/_filemanager/file/55665005182.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_off0000bcbb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBCBB 11196 bytes
SHA-256: 764c8da1ff8db6b9772ca94a4641371b641ce7035faf361df766cb5f34b94377
font_01_sfnt_off0000d6da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6DA 16512 bytes
SHA-256: 8e8e0b4fbb3fdc3bd38cdccca5aaec4af598badc334ddd56c6a45758cfb22345
font_02_sfnt_off00010183.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10183 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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