Malicious PDF — malware analysis report

Static analysis result for SHA-256 ffc161bd81999143…

MALICIOUS

PDF

90.8 KB Created: 2021-06-29 21:25:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e58fc33515bc690179ad2dd6bc3e2606 SHA-1: 25f2022cd914cb79db8430677e227a9d01a0a468 SHA-256: ffc161bd81999143c43a451bb56a613903b925a9e9af8105e84d30c57c20a5b5
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to potentially compromised WordPress sites or disposable hosting, suggesting an attempt to redirect users to malicious content. 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 0.9961

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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/kipaparedemutiveta.pdf
    • http://mu-rrrc.com/userfiles/file/togutalikakabepuputavinug.pdf
    • http://www.whirlpool-beachcomber.at/wp-content/plugins/formcraft/file-upload/server/content/files/1608dec8cb4b03---konipikowevorajotokan.pdf
    • https://apoc.com.au/wp-content/plugins/super-forms/uploads/php/files/6e0523e52e38f3d0b08e396a9e83a387/vidagamiwaz.pdf
    • http://www.hptindia.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082472ee2265---69990811084.pdf
    • http://wenxuezj.com/images/File/52613753532.pdf
    • http://sity-luxe.ru/userfiles/file/48512835828.pdf
    • https://staffxrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/3aaacf9b10bb89dead655407e984acfb/xozexuzoxadoronakonorokem.pdf
    • http://baharemadinah.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a431c8024da---58501240650.pdf
    • http://jnafarms.com/clients/864068/File/93321447330.pdf
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160afa9c57329e---25226235485.pdf
    • https://www.oasipizza.it/wp-content/plugins/formcraft/file-upload/server/content/files/160c9864d7e572---56029264490.pdf
    • http://15889163.com/ckupload/files/18975821890.pdf
    • https://allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/35568a672d10d056e3c9e92959ce4664/kijuwovobes.pdf
    • https://istanajp2.com/contents//files/pejomilevom.pdf
    • https://rittenhousesmiles.com/wp-content/plugins/super-forms/uploads/php/files/62d028e910cf9c45e77a27413dfe166f/fosutubebebutoxesowovut.pdf
    • https://vashadvokat82.ru/wp-content/plugins/super-forms/uploads/php/files/e464562c916a18fc088afb425ff9b120/javebevazujezowiwuvuzegir.pdf
    • https://mymovingestimate.com/wp-content/plugins/super-forms/uploads/php/files/1c6d1580b570ce822d758c239d4f783e/lemator.pdf
    • http://balogmihaly.hu/UserFiles/file/6040264278.pdf
    • http://socialbomjesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606ca415f29f4---84872859148.pdf
    • https://anzmrrn.org/wp-content/plugins/formcraft/file-upload/server/content/files/1609258140e026---78601562335.pdf
    • http://zonweringnederland.com/ckfinder/userfiles/files/xalijozeke.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=ruby+chard+growing
    • 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_off00010046.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10046 16792 bytes
font_01_sfnt_off00011858.bin
09dc66e5dadc82b94a614b2372f1fc760e62d5b9969313ad77cb4f7f4de0d269
pdf-font-stream PDF embedded font (sfnt) at offset 0x11858 17048 bytes
font_02_sfnt_off000144b5.bin
accc1be0a9af3a533832acde0cac22c9c5cbff8f2455cbba2410b4675bbed725
pdf-font-stream PDF embedded font (sfnt) at offset 0x144B5 10692 bytes