Malicious PDF — malware analysis report

Static analysis result for SHA-256 b77360e3e9567035…

MALICIOUS

PDF

84.7 KB Created: 2021-09-18 21:50:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: b6ac33e21890484d77764b84a3ee1f1d SHA-1: 2300f27d307be3d533a6f6eac10f141cefb940e6 SHA-256: b77360e3e9567035c25c6feb4e76b77180a96561f8ab1c3161e37a252172c533
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample is a PDF document flagged by ML classifiers and ClamAV as malicious. Heuristics indicate it functions as a link farm and a callback phishing lure, prompting users to call a phone number in a context of billing or security issues. While no scripts were directly extracted, the presence of external URIs and the nature of the heuristics suggest it may exploit PDF vulnerabilities or lead to further malicious content. The document body is heavily obfuscated and unreadable.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://voijin.com/userfiles/files/20866872956.pdf In PDF document text
    • https://www.bountyvacation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614220de3d9ad---41160974870.pdfIn PDF document text
    • http://fygl.net/uploads/file/040412585408.pdfIn PDF document text
    • https://cmoretv.com/userfiles/fimopisofiliwatijujibesiw.pdfIn PDF document text
    • http://doubles301.jp/files/ckeditor/files/bitumiw.pdfIn PDF document text
    • https://chataigne-cevennes.fr/imgs/files/xelasolig.pdfIn PDF document text
    • https://www.opdrrustukalac.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613665fa632e0---zumemelesoperupufitu.pdfIn PDF document text
    • http://hud101.vn/webroot/img/posts/files/lokuxutodinuzelubadis.pdfIn PDF document text
    • http://outspokenholland.com/userfiles/fckFile/20210913221010.pdfIn PDF document text
    • https://www.xcelsus.de/wp-content/plugins/formcraft/file-upload/server/content/files/16131519caa192---17869873404.pdfIn PDF document text
    • http://bielwod.com/userfiles/file/44084370211.pdfIn PDF document text
    • https://xlux.vn/wp-content/plugins/super-forms/uploads/php/files/296thituapondnp0uagf5db9us/gipalaxavu.pdfIn PDF document text
    • https://812423.qqtogeljackpot2.com/contents/files/movojosasulila.pdfIn PDF document text
    • http://aburobocon2019.mnb.mn/uploads/files/danamoxolojer.pdfIn PDF document text
    • http://travel-door.com/userfiles/file/3000128860.pdfIn PDF document text
    • http://hwangtosidae.com/userData/ebizro_board/file/2479546475.pdfIn PDF document text
    • http://naoshima-habitant.com/images/blog/file/7362495079.pdfIn PDF document text
    • https://sikahaiphong.com/images/news/files/zuragosokisi.pdfIn PDF document text
    • http://prvugkh.ru/uploads/files/manegivikagotogexovemeg.pdfIn PDF document text
    • http://dohertylaw.net/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/burilujilujojuxadulo.pdfIn PDF document text
    • http://synhbio.com/upload/files/mulokujadasedidip.pdfIn PDF document text
    • http://elitaliaweb.it/upload/file/fojuxuseki.pdfIn PDF document text
    • https://twinslock.com/ckfinder/userfiles/files/43290384342.pdfIn PDF document text
    • https://beautyyaurient.com/editor_upload/file/64070131812.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=how+to+find+the+h+and+k+of+a+quadratic+functionPDF 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_off0000e612.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE612 17896 bytes
SHA-256: 6da0ada06b70069e20ab0550148165aa5794ccca41a8015e4b741243f2ee366c
font_01_sfnt_off00011445.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11445 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012c5c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C5C 10776 bytes
SHA-256: 30c561bc65d087297461fb33c78e9bb0b0bc6407854dbb2aa4fbec601c921ead

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