Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac8a7e5941a1a37e…

MALICIOUS

PDF

76.4 KB Created: 2021-09-02 06:52:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e8e28f4d13f1de3e931ea8eda3a2bf89 SHA-1: e306896ba7d3c98ef3f1210d3cddc18478331857 SHA-256: ac8a7e5941a1a37ea57adac96dc35ba2d18adee2b1edfed0b75b44de78596cf4
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded links pointing to compromised WordPress sites and other disposable hosting, indicating a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. No scripts were extracted, but the heuristic firings point to the use of external URLs for malicious purposes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://vivaibonomo.it/userfiles/files/visikelamivozejok.pdf
    • http://bangdientunhk.com/upload/files/dajos.pdf
    • http://lbs.ac.at/wp-content/plugins/super-forms/uploads/php/files/rkcae9mf12vb78oc6l3k85u64m/15470522974.pdf
    • https://www.emma-solutions.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607c97b6f0bf8---67981310681.pdf
    • http://www.juniorcollege.cl/ckfinder/userfiles/files/57930242281.pdf
    • https://nikunjfoundation.org/ckfinder/userfiles/files/94085223800.pdf
    • http://worthingtonpark101.com/userimages/73128613027.pdf
    • https://sumangold.net.vn/wp-content/plugins/super-forms/uploads/php/files/09p7dgc7gc0d5ao8h898v81voi/66700247650.pdf
    • https://airflow-skateboards.com/userfiles/files/fuwules.pdf
    • https://mbamantra.com/ci/userfiles/files/3776524575.pdf
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9c01c39d3a---92117452865.pdf
    • https://autoteam.in/ckfinder/userfiles/files/93423418010.pdf
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/opndiulev70udk98ir4cq95mg3/51532943268.pdf
    • http://viprealestatebrokers.com/userfiles/files/viwiniwub.pdf
    • https://humble-brag.com/wp-content/plugins/super-forms/uploads/php/files/c0vq8at6u21006q03gd3egjomb/luwudobereganufeba.pdf
    • https://taxiparga.com/wp-content/plugins/super-forms/uploads/php/files/c7c40ac8a6a45649dd054dee330eb6c9/tubokubimenirurajoxuw.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=belling+the+cat
    • 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_off0000c93e.bin
8f890cbbf5275db89fde5ec77548b1a3961c30bc4f33e3533cb5b5a1c1210f89
pdf-font-stream PDF embedded font (sfnt) at offset 0xC93E 10176 bytes
font_01_sfnt_off0000dfea.bin
475e4fb4e58b80ab2f24c9dcd27d65301cfde68eb1947b1a875f2efcf137be18
pdf-font-stream PDF embedded font (sfnt) at offset 0xDFEA 17088 bytes
font_02_sfnt_off00010c06.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10C06 16792 bytes