Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8ccfbf505675961…

MALICIOUS

PDF

74.6 KB Created: 2021-09-05 11:46:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 837c21d5a6535721000314719ef7b018 SHA-1: 21e1259288bddff58e8429b73acdd6848056dfff SHA-256: a8ccfbf5056759612f8cf4ac8e4eddf7b0019cf6d1d86f449dd5f7c27176d30f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample is a PDF document identified as malicious by ML classifiers and ClamAV. It contains numerous external links, many pointing to compromised CMS upload directories or disposable hosting, suggesting a phishing or malware distribution lure. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, with no clear user-facing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://crewmak.ru/uplcv?utm_term=nature+and+scope+of+operational+research+pdf PDF link annotation
    • https://la-klamm.org/Files/files/21107833330.pdfIn PDF document text
    • https://asiaviews.org/wp-content/plugins/super-forms/uploads/php/files/d8eefsf6qq4n67stqs3vsqf6e0/bagekidurolavujojulukol.pdfIn PDF document text
    • https://www.eecpowerindia.com/codelibrary/ckeditor/ckfinder/userfiles/files/56917396909.pdfIn PDF document text
    • https://www.citysecurity.org.uk/wp-content/plugins/super-forms/uploads/php/files/7ves3drqjgadfiajds8lcqqhar/76640148160.pdfIn PDF document text
    • http://sciattella.net/images/file/dewapikobitaro.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160abcdfbe7cc9---80000168136.pdfIn PDF document text
    • http://ahcxdq.com/uploads/file/040552216850.pdfIn PDF document text
    • https://hiroyoung.com/data/files/moninunabiromopuweb.pdfIn PDF document text
    • http://sushiyaslo.com/uploads/files/ruxeluxuwa.pdfIn PDF document text
    • https://www.justgym.co.za/wp-content/plugins/super-forms/uploads/php/files/hbqvlnkg46te53phn3o6hs12lg/guvefonufilizetet.pdfIn PDF document text
    • http://joyearland.com/ckfinder/userfiles/files/75435699418.pdfIn PDF document text
    • https://prikolnaya.com/wp-content/plugins/super-forms/uploads/php/files/98ca623a9a2a58c9a0ae12f26f4f8247/zoketilefusedux.pdfIn PDF document text
    • http://kondicionery-vidnoe.ru/upload_picture/file/bexeguzefuk.pdfIn PDF document text
    • http://accurateverdicts.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bec076691f3---girefekepiwofafiwowox.pdfIn PDF document text
    • http://becro-plast.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160c9e5927ef80---81155762732.pdfIn PDF document text
    • https://deedpoll.sg/wp-content/plugins/super-forms/uploads/php/files/26300c789e564ebab72775d319ee58c2/xipunaniloguloxusenowibat.pdfIn PDF document text
    • http://videoacceso.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bf5af4f1eb3---61346282419.pdfIn PDF document text
    • https://bulendengin.com/upload/ckfinder/files/92422377324.pdfIn PDF document text
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607dc851d3f8a---28848382369.pdfIn PDF document text
    • http://iccj.jp/images/uploads/fckeditor/file/49661809424.pdfIn PDF document text
    • http://mopron.ru/upload/files/datidalibelulujunuwiv.pdfIn PDF document text
    • http://breakevenpoint.pl/uploads/editor/file/49152070844.pdfIn PDF document text
    • https://www.cr-sdc.org/wp-content/plugins/super-forms/uploads/php/files/b2d5599108ae299c1eed93fbab2e2ff8/tojimibujuri.pdfIn PDF document text
    • https://digiconelectronics.com/media/jasetuzibagifigozozilotu.pdfIn PDF document text
    • https://mycocoa.org/images/upload/files/xanuxubijalaxijadam.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_off0000c41b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC41B 15580 bytes
SHA-256: 3e28d71fa5844fde1e6ba499500cd9084b52d304552e0646f92df42cba64c5d0
font_01_sfnt_off0000eb8c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB8C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000103a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103A3 10796 bytes
SHA-256: ae439ea422d2d938d1a282d687363c14e459e8279f69a9ec2f98f81702712579

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