Malicious PDF — malware analysis report

Static analysis result for SHA-256 b523ce8dee834649…

MALICIOUS

PDF

81.4 KB Created: 2021-08-23 12:15:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 5992183a364da77ac68098e565da8ecc SHA-1: adaccb64206a5c1f4c8cf32ca8c77c8ed2323119 SHA-256: b523ce8dee834649202e9033aaa6d7cef067510bc2d721ade3b44ae3c04942b9
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was flagged by multiple heuristics as containing a link farm pointing to compromised CMS uploads and disposable hosting. The ML classifier and ClamAV also identified it as malicious. The embedded URLs are likely used to redirect users to phishing sites or download further malicious content, aligning with a spearphishing attachment attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 7

  • 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 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 https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160984573dd243---99524794513.pdf In PDF document text
    • http://ljhalls.com/wp-content/plugins/super-forms/uploads/php/files/8967ea423c3a0d0299afbf68f6dd5fe9/najinamaboxowidukuxire.pdfIn PDF document text
    • http://tamker.hu/userfiles/file/62636506093.pdfIn PDF document text
    • https://thinkhigh-tech.com/d/files/72243858802.pdfIn PDF document text
    • https://jss-moms.si/upload/File/joxajomaditatodidapirelu.pdfIn PDF document text
    • http://hanauhrova.cz/files/rufebomow.pdfIn PDF document text
    • https://otdelkamos.ru/wp-content/plugins/super-forms/uploads/php/files/aee1ba9439ee1e3cda389b7812a42821/9574905417.pdfIn PDF document text
    • http://bafiti.com/sklep/userfiles/file/famiwisoviroj.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160797bf871b27---gigab.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/6lel7ss9ba45qda2qqtj97ta34/tabifazekepuvugowikun.pdfIn PDF document text
    • http://sentezetutmerkezi.com/upload/ckfinder/files/wowutikubovivununi.pdfIn PDF document text
    • https://www.rath-catering.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bb00b889a29---lidarokuwipazukovu.pdfIn PDF document text
    • https://perfecthospital.org/FCKeditor/file/bawuxileveramimal.pdfIn PDF document text
    • http://yulintimber.cn/d/files/65062813097.pdfIn PDF document text
    • http://erimti.com/userfiles/file/47687532379.pdfIn PDF document text
    • https://perfecthospitals.org/FCKeditor/file/54595075262.pdfIn PDF document text
    • https://kantankacreative.com/wp-content/plugins/super-forms/uploads/php/files/33d082e7231d9007c06a4851e263d383/powosukavo.pdfIn PDF document text
    • https://www.llgnjinc.com/wp-content/plugins/super-forms/uploads/php/files/f2ca646d843e17c91fec274080192e40/mekesiramefirenuji.pdfIn PDF document text
    • http://glenbrooksouth1970.com/clients/1/17/17fc1bd13d5538a69f39d58c869d2fc5/File/gopinopenegunofowedal.pdfIn PDF document text
    • http://aggengr.com/uploads/CMS/file/68311009816.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=5+weeks+from+conceptionPDF link annotation
    • 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_off0000db63.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB63 17364 bytes
SHA-256: cfe17b5e0b5fa119f5b92b2671cdf5d547f60cf5af3dc6c2b7629b7798e2ada0
font_01_sfnt_off00010821.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10821 10648 bytes
SHA-256: 7c5de28c1d45998f9851ff238a7628db5848639e5e5d856fc32e66508fbb3625
font_02_sfnt_off000120a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120A3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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