Malicious PDF — malware analysis report

Static analysis result for SHA-256 c7bfa85255489a95…

MALICIOUS

PDF

72.0 KB Created: 2021-06-20 23:23:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: b4bb6bb2e6347067d0bdf4c35690a05a SHA-1: e1237b34fde4d604cfb322a97782cd0b95275e71 SHA-256: c7bfa85255489a950de5e256b91b6abb8774f4902bee8ea1c51435986f4ba03f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file was detected as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It contains numerous links to external websites, many hosted on compromised CMS platforms or disposable domains, suggesting a link farm designed to redirect users to malicious content. The document body, though heavily obfuscated, appears to be a lure related to 'algebra 2 arithmetic sequences worksheet answers', likely intended to trick users into clicking the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://nacyc.jp/Upload/file/81431768514.pdf
    • http://cn-polylysine.com/d/files/48684293172.pdf
    • http://ats-dz.com/userfiles/file/pafeworafaxomoso.pdf
    • https://lsp.od.ua/wp-content/plugins/super-forms/uploads/php/files/14lmprtfaq279jk6f2ft464537/xedazagasixomisiseg.pdf
    • https://www.swx.global/wp-content/plugins/super-forms/uploads/php/files/4fe791e7cb49500f90ece830432182e0/xapuri.pdf
    • http://amfmeg.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607d89e5388e1---83302420766.pdf
    • https://www.tessilgiada.it/wp-content/plugins/formcraft/file-upload/server/content/files/16099cf2789b87---58439940257.pdf
    • http://www.lavalledesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079efc13692b---18293726073.pdf
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/160c94b9776ed1---38178200870.pdf
    • http://www.akutrans.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0d3ab826be---72571054435.pdf
    • http://www.grundys.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160bcf79a615fb---dabuvimodugudusoxan.pdf
    • https://ifacemount.com/wp-content/plugins/super-forms/uploads/php/files/dtr8ok656srk6c2c8409e9p9mu/26868937986.pdf
    • https://ifacemount.com/wp-content/plugins/super-forms/uploads/php/files/n3fmpmq9suprqmkcql9gc4mh0i/42848894599.pdf
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16086c7e5ccd58---57857145204.pdf
    • https://szallas-karpatalja.com/upload/10011146238.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=algebra+2+arithmetic+sequences+worksheet+answers
    • 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://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000db14.bin
f9d819b9248cf2758680de5bdcb9186255aa3bc5ab4c6d3a7f7ba32bd980a93f		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDB14 5756 bytes
font_01_sfnt_off0000ee96.bin
0fc16417ac041a9f2b157f373e2cc867c09c945f26f34ee7e8f4bfee80cc8643		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEE96 10680 bytes

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