Malicious PDF — malware analysis report

Static analysis result for SHA-256 b522695082554838…

MALICIOUS

PDF

86.3 KB Created: 2021-07-21 15:29:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 9a1945599bc7066b56eb7241347a23e1 SHA-1: 4bb42ec4190c15f1af829efcbbe199f9152e08c4 SHA-256: b522695082554838c66523ede5b1382f4c15aeafc3f8188cc0654f4a0bd00512
156 Risk Score

Malware Insights

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

The sample was identified as malicious by a ML classifier and ClamAV, with the latter detecting it as 'Pdf.Phishing.Trojan'. Heuristics indicate it functions as a link farm, with numerous URLs pointing to compromised CMS upload directories. The PDF document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://arnold-sitter.com/CKEdit/upload/files/ritozasatemorimi.pdf
    • http://www.stratcareerservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a62758e7fdf---tilugubozedijositubitek.pdf
    • http://www.monts.sk/upload_images/file/73289217436.pdf
    • http://amon-syotengai.com/userfiles/file/fedom.pdf
    • https://paloaltospeakerseries.com/wp-content/plugins/super-forms/uploads/php/files/890d34d3dfaf8e8eee3d3c523b7e8f83/77605666656.pdf
    • http://www.alquilerbares.com.ar/wp-content/plugins/formcraft/file-upload/server/content/files/160831d09af533---58434366023.pdf
    • https://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160942371739ac---64418785531.pdf
    • https://www.lang-mayer.de/wp-content/plugins/formcraft/file-upload/server/content/files/160950d7d3235c---70158902614.pdf
    • http://salonorganica.ru/upload/files/sonareneje.pdf
    • https://primeodontorj.com/wp-content/plugins/super-forms/uploads/php/files/6a41ef8a8199b2c7dee3eb525d7d2005/vamaf.pdf
    • http://www.skupp.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160d7e0834d19b---kuguxiropemutebo.pdf
    • https://amrapalispot.com/userfiles/file/zetiwafifaxarapijokafor.pdf
    • https://asthasupermarket.com/userfiles/file/favoxutuparakejimul.pdf
    • https://hirurgija.me//files/mokerez.pdf
    • https://webmodels.studio/wp-content/plugins/formcraft/file-upload/server/content/files/160a40fa929023---suwituba.pdf
    • http://svaz-podnikani.cz/files/file/23743510349.pdf
    • http://www.homefacelifters.com/wp-content/plugins/super-forms/uploads/php/files/c9f05238cfba61495e1450626aeab2a4/peximeruxiwimitik.pdf
    • https://stagerightstaging.com/wp-content/plugins/super-forms/uploads/php/files/270e534fc3c5f46e61326ee62e1c8423/86404387869.pdf
    • https://tocgia247.com/wp-content/plugins/super-forms/uploads/php/files/64r7cq7tl178jmb0tkdg4qfp32/mositadalinirewazototinav.pdf
    • http://cmtsport.com/pliki/50645780251.pdf
    • http://evola.it/userfiles/files/senezakolujupar.pdf
    • http://dgjst.com/upfile/file/nerogesob.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=contract+law+and+arbitration+pdf
    • 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_off0000eeb8.bin
06c1e993c074bbf8123dd4077b5f1c310397a937c7bac6e6b0452ee6e7b0bcc9
pdf-font-stream PDF embedded font (sfnt) at offset 0xEEB8 10572 bytes
font_01_sfnt_off000106c9.bin
3b63cc03d6bccdf5ed9f3f0b0f3ccc6ece996e8f91701919f55c520370e9eb84
pdf-font-stream PDF embedded font (sfnt) at offset 0x106C9 17112 bytes
font_02_sfnt_off00013387.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x13387 16792 bytes