Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8a37b3794ab3686…

MALICIOUS

PDF

82.4 KB Created: 2021-09-14 04:12:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 20c07df08509443c7614c26d50c97812 SHA-1: 44d3a4b0c3073b41005eed304a95c5c2ecddeff8 SHA-256: c8a37b3794ab36865bd0896ecf8e5f80937af6147fd4a211d7be2ea3e7197cef
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. It contains numerous external links, with several pointing to compromised CMS upload directories, suggesting a phishing or malware distribution lure. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather as a container for malicious links.

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 http://kovofilm.cz/userfiles/file/vemupimuxifimaxalogobeg.pdf In PDF document text
    • http://twtqedu.com/userData/ebizro_board/file/gasibubenidivebi.pdfIn PDF document text
    • http://paddockj.com/user_data/editor/ckfinder/core/connector/php/upload/files/65929263504.pdfIn PDF document text
    • https://2acontractor.it/images/file/jiludobufaliduzoris.pdfIn PDF document text
    • http://e-hematologica.pl/users/file/45337235120.pdfIn PDF document text
    • http://www.omt.ntou.edu.tw/ckfinder/userfiles/files/4576229762.pdfIn PDF document text
    • http://cungcapbaoduongcuanhatban.com/upload/files/22229575183.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/161358a1996620---11579865269.pdfIn PDF document text
    • http://denetimmusavirlik.com/userfiles/file/juvevij.pdfIn PDF document text
    • https://camphacement.vn/upload/files/92200384135.pdfIn PDF document text
    • http://eichler-kammerer.de/45167990049.pdfIn PDF document text
    • http://brandiassociati.it/userfiles/file/vinajekumow.pdfIn PDF document text
    • http://daejonggyoyc.com/userfiles/file/20210904220035.pdfIn PDF document text
    • http://ed-union05.ru/files/file/29736504355.pdfIn PDF document text
    • https://milosislandrooms.gr/userfiles/file/24478437161.pdfIn PDF document text
    • https://leuphuotcamap.com/uploads/image/files/10965815079.pdfIn PDF document text
    • http://epoxidice.ro/mm/file/38851314329.pdfIn PDF document text
    • http://ckm-machinery.com/userfiles/files/60844148379.pdfIn PDF document text
    • http://perfectthesale.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f16f092eef---70107671655.pdfIn PDF document text
    • http://uyaviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132729f1d1a7---60865336605.pdfIn PDF document text
    • https://www.cdscabling.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613275bcb7eee---18861094526.pdfIn PDF document text
    • http://www.ferm-matic.fr/upload/file/niretunofiki.pdfIn PDF document text
    • http://arqing.es/ckfinder/userfiles/files/webibirijukigizupil.pdfIn PDF document text
    • http://driscollandgibson.com/images/edit_images/file/22009298436.pdfIn PDF document text
    • https://truckforceone.com/upload/editor/file/47034080479.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=how+to+enable+the+disabled+app+in+androidPDF 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_off0000d849.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD849 10704 bytes
SHA-256: 85f8a1234ea1e127e697b6d5e4dde5564f63f4f4a6142a9d800ed1f089a6325c
font_01_sfnt_off0000f08b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF08B 19676 bytes
SHA-256: 947004cabffc732616ec44cef4ea89b5cf01027e4d7f0a611ef1872414dae1c1
font_02_sfnt_off000123c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123C4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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