Malicious PDF — malware analysis report

Static analysis result for SHA-256 40c247538e3b0aa4…

MALICIOUS

PDF

73.0 KB Created: 2021-07-01 00:49:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b428f47f5af48fad629dab90d3f704ef SHA-1: 75aa782eb016b4c11425e1a961c952c3045de4d3 SHA-256: 40c247538e3b0aa4b77ae2428ae9d0172964905c997930ed1db21895dd4128dd
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV detecting it as a phishing trojan. It contains a link farm pointing to numerous compromised WordPress upload directories and other disposable hosting, suggesting an attempt to distribute malicious content or host phishing lures. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but serving as a container for these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://marcth.pl/media/fck/file/jabefu.pdf
    • https://eyestech.in/wp-content/plugins/super-forms/uploads/php/files/hns535a8nijem1isolhg6cdtla/kesixavinafafemaxisab.pdf
    • https://www.dishdivvy.com/wp-content/plugins/super-forms/uploads/php/files/daa3139c3aab9c9c06ebd025dde54e3a/34090575487.pdf
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/samocchp2rnhbap9kj0hj75p45/28587236757.pdf
    • https://webmodels.studio/wp-content/plugins/formcraft/file-upload/server/content/files/1606cab8f8b597---62706404439.pdf
    • https://powermailer.in/userfiles/file/47469054469.pdf
    • https://gdr.co.il/wp-content/plugins/super-forms/uploads/php/files/d35ef36b90d8beedd31adea7b30d3f48/24615389200.pdf
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608874269af01---nodopefinugufumevu.pdf
    • https://www.truesdalepainting.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606ca26f07832---damot.pdf
    • https://www.chinacimctrailer.com/wp-content/plugins/super-forms/uploads/php/files/1af560667938bf5f7adcd80dc19389c7/tijozi.pdf
    • http://drapa-technika.cz/UserFiles/File/78419034028.pdf
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b77d566416f---92874312999.pdf
    • https://abugfreemind.com/userfiles/file/93978545870.pdf
    • https://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160b3f8d9283f9---kewalavinonademikumaz.pdf
    • https://vestol.bg/files/file/2697451105.pdf
    • http://f-kcc.jp/user_data/userfiles/files/50187813166.pdf
    • http://therealmccoyfamilyreunion.com/clients/f/f9/f9ea119420dddc0cc5ac7622830b9f68/File/83996225208.pdf
    • http://accessiblevehicleservices.com/userfiles/file/pababexijo.pdf
    • http://homeopathyhk.com/files/rofik.pdf
    • http://pozitron-s.ru/userfiles/file/84312719010.pdf
    • https://www.cukoyem.com.tr/wp-content/plugins/super-forms/uploads/php/files/s62g1jeshpolk646j8ts9gl0i3/85051626469.pdf
    • https://tocgia247.com/wp-content/plugins/super-forms/uploads/php/files/mdfrlu6stp54sqjehsg20312fk/vewotufunulijuxix.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=confession+times+near+me
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000bd9d.bin
d6efbc284c56d89d1b74eaf77b7ff7bf017882b5adb3d4b52a4e4051ed0ff0d2
pdf-font-stream PDF embedded font (sfnt) at offset 0xBD9D 16104 bytes
font_01_sfnt_off0000e7a9.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE7A9 16792 bytes
font_02_sfnt_off0000ffc0.bin
85773b63d9760b877e79a3e0cea606071e3283c3bd5f0afb7aa31f1b6dc4af63
pdf-font-stream PDF embedded font (sfnt) at offset 0xFFC0 10360 bytes