Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f21f6718424efac…

MALICIOUS

PDF

82.9 KB Created: 2021-09-06 18:30:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 93d4d0ae0cf6969b0ceb433f919217ba SHA-1: 2627896d540fb518c2809b93ee5e54ead72db095 SHA-256: 4f21f6718424efac76d061a09623bd9740193b1230d773bdc74e60c9db11457a
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV detecting it as a phishing trojan. It contains numerous embedded URLs pointing to compromised WordPress sites and disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of malformed streams and external URI firings indicates an attempt to exploit PDF vulnerabilities or deliver malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

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
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://pixomot.ru/uplcv?utm_term=panchatantra+stories+download+pdf PDF link annotation
    • https://vizzzio.ru/wp-content/plugins/super-forms/uploads/php/files/4cc92bdfe7a4b694b473955c6ac98de3/zasudusipimej.pdfIn PDF document text
    • https://fjordancv.info/wp-content/plugins/super-forms/uploads/php/files/ea11ea683f986c8fd7d3b23fd9b1c19a/82916805248.pdfIn PDF document text
    • http://vibrosystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1610ce0c7eb70a---85472770249.pdfIn PDF document text
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609ecf726fffb---14247757516.pdfIn PDF document text
    • https://www.scanworld.se/wp-content/plugins/formcraft/file-upload/server/content/files/1606eb4d40acff---zudemerabadoxoruninadoto.pdfIn PDF document text
    • http://100gastro.cz/soubory/files/fagubusanulokiwemegofibu.pdfIn PDF document text
    • http://valifyrepapillon.com/clients/6/68/68e1c6a84db99a04c21676ff826d6e37/File/rojawariru.pdfIn PDF document text
    • http://www.oschouston.com/osc/wp-content/plugins/formcraft/file-upload/server/content/files/16072e0c5144fd---69278147747.pdfIn PDF document text
    • https://estidevelopers.com/wp-content/plugins/super-forms/uploads/php/files/b05a0ec336fe3f01f2b547cef22ae0bc/24166423225.pdfIn PDF document text
    • http://ptk-astana.kz/wp-content/plugins/super-forms/uploads/php/files/6a047d49ab22e0c55f4661417f1ed910/42922585978.pdfIn PDF document text
    • http://architects-desk.com/uploadsfile/lerizuzadajakufito.pdfIn PDF document text
    • https://vegan-eshop.cz/data/file/81347672862.pdfIn PDF document text
    • http://peggylittlelawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/79535521585.pdfIn PDF document text
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/160bd5d78a258c---877663933.pdfIn PDF document text
    • https://dm288.com/slicice/file/36450025622.pdfIn PDF document text
    • https://40parables.com/wp-content/plugins/super-forms/uploads/php/files/7d0f00d37e861f63ff8f89eef279b532/56095682685.pdfIn PDF document text
    • http://handlpc.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/vodubolev.pdfIn PDF document text
    • http://narnivet.com/userfiles/files/kuwirun.pdfIn PDF document text
    • https://nikken-engineer.jp/export/sd205/www/jp/r/e/gmoserver/8/6/sd0748886/nikken-engineer.jp/fckeditor/upload/file/banonomurite.pdfIn PDF document text
    • https://artedeeducar.com.br/ckfinder/userfiles/files/rigefofomedewisu.pdfIn PDF document text
    • https://kaplaitalia.it/userfiles/files/tafisumugeginusokokude.pdfIn PDF document text
    • http://dainichiji.com/upload_ckr/files/42935940655.pdfIn PDF document text
    • https://law.myvzl.com/wp-content/plugins/super-forms/uploads/php/files/37pst2ak6aiu3i5pr25i47r44v/nubuvajeralawate.pdfIn PDF document text
    • http://gazetavk.ru/img/file/25388764291.pdfIn PDF document text
    • http://silver1979.com/upload/file/65806354915.pdfIn PDF document text
    • http://ndt-tl.ru/upload/file/bomugaxaxusugavaxikisob.pdfIn PDF document text
    • http://lovewhereyoulv.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/ece2373225bd1c89fd66c86c87251a26/nafinejexes.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_off0000dd3e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD3E 18320 bytes
SHA-256: 7bb709bf8f09b73b97914c5a964f8c56e9e97845783951edb221016d32387a74
font_01_sfnt_off00010c81.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C81 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012498.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12498 10804 bytes
SHA-256: d19fa40782e641e623255f37de622083fdd1b91f940d88fb8884383f8afa2eba

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