Malicious PDF — malware analysis report

Static analysis result for SHA-256 9b779166b9efc3f7…

MALICIOUS

PDF

79.5 KB Created: 2021-09-02 19:09:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 636279a10c63a70faeb5bb158959bcfa SHA-1: 9e6079a7e0503165e8a323af67d52767e2bb1aea SHA-256: 9b779166b9efc3f7a66c3b5436f718d3a7237461fd590ce47aea4a6b9bc94c38
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing or trojan. It contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, indicating a link farm designed to lure users to malicious destinations. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but serving as a container for the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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 https://laptoptranganh.com/data/dulieu/files/34525008347.pdf In PDF document text
    • http://usefchina.com/uploadfile/file///2021072805245965.pdfIn PDF document text
    • http://autoscuolapezzano.it/userfiles/files/xisifa.pdfIn PDF document text
    • http://ueros.fr/admin/ckfinder/userfiles/files/97353281032.pdfIn PDF document text
    • http://yuhenganquan.com/userfiles/file/20210708110639_1715879107.pdfIn PDF document text
    • http://marty-triple-m.ch/inhalt/files/kaxaliwelesijopadudig.pdfIn PDF document text
    • http://novo-foto.ru/ckfinder/userfiles/files/mogumelozakog.pdfIn PDF document text
    • http://allegroescrow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c6c77af127c---jipak.pdfIn PDF document text
    • https://mepho.hu/ckfinder/userfiles/files/mozava.pdfIn PDF document text
    • https://razdolle.by/wp-content/plugins/super-forms/uploads/php/files/j1j6lhtjdomvto8suvo3mfmcv4/89537743878.pdfIn PDF document text
    • http://www.sarajevo-inn-grunewald.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076379f7c3e9---14079453295.pdfIn PDF document text
    • http://www.kevinbrooks.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160789cd9bb2d7---8623736532.pdfIn PDF document text
    • http://dmn.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160ad8cb997938---75004801239.pdfIn PDF document text
    • http://brette-animation.com/userfiles/file/defijafepuleki.pdfIn PDF document text
    • http://www.telsercom.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bff7f18c402---48239058795.pdfIn PDF document text
    • https://skyzoan.com/cake/beta/userfiles/file/vimomajilorumomotuto.pdfIn PDF document text
    • http://www.onegelha.com/wp-content/plugins/super-forms/uploads/php/files/4017a1bb505b907ee9ec4377b8fd9ee9/sadiduvozozasidibas.pdfIn PDF document text
    • http://heizler.hu/files/file/79913076943.pdfIn PDF document text
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/m1euab9j7a8g02bikbfa1l40b2/xipiwujemexujopelakopazap.pdfIn PDF document text
    • https://cullinanconstruction.com/wp-content/plugins/super-forms/uploads/php/files/qcpnd04bndoei3kif8l9f92rck/57750061441.pdfIn PDF document text
    • https://www.pennlighting.com/wp-content/plugins/super-forms/uploads/php/files/c4bdf5aeeee9d5328be95a39baa6e116/kerux.pdfIn PDF document text
    • http://mintaialuminum.com/d/files/50375742452.pdfIn PDF document text
    • https://thingstodobahrain.net/ckfinder/userfiles/files/18157294752.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=quizas+quizas+quizas+guitar+pdfPDF 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_off0000d272.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD272 10636 bytes
SHA-256: f09577f51ca6cdaad40824e5ce12084f9c2f059da01789b27114eb63908ea39a
font_01_sfnt_off0000ea87.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA87 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010299.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10299 17624 bytes
SHA-256: 8ea3e58fed0a404d9b8681772c1a82fc8766d6a0eb0d1bd24a5ff3af8310f05e