Malicious PDF — malware analysis report

Static analysis result for SHA-256 681f2edb1816dc34…

MALICIOUS

PDF

77.1 KB Created: 2021-09-06 09:30:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 367556fad46da24f83d69df2879e76fd SHA-1: 792df08e40df09a4c0d2627072213d01dc1f2d56 SHA-256: 681f2edb1816dc3410e68ab649392560324b6cc947f9de0ba30edfb2f1b19863
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document identified as malicious by ClamAV and an ML classifier. It contains numerous external URIs, many of which point to compromised WordPress sites, suggesting a link farm designed to redirect users to malicious content. The presence of embedded JavaScript, though not explicitly detailed in the provided evidence, is a common technique for exploiting PDF vulnerabilities or initiating further malicious actions.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16076233e28913---vupotapawaragopavojofi.pdf In PDF document text
    • https://www.grandiosa.is/wp-content/plugins/super-forms/uploads/php/files/rh9knm5vl360ao8bggnlm5fbd3/44324967691.pdfIn PDF document text
    • http://nollve.com/img/editor/image/file/dunetavezopufaluli.pdfIn PDF document text
    • http://digemnd.com/UserFiles/file/semabekitefinifitupo.pdfIn PDF document text
    • http://omni-links.com/images/blog//file/65903761719.pdfIn PDF document text
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/160c20dc5a294a---91975970518.pdfIn PDF document text
    • http://kindervakantieweekdeurne.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160ae8bbe98560---61867274624.pdfIn PDF document text
    • http://www.lavalledesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/16099224c7102b---38816092742.pdfIn PDF document text
    • http://thunderstar.cn/userfiles/file/20210503060123836581959.pdfIn PDF document text
    • https://drivingschoolofnorthtexas.com/wp-content/plugins/formcraft/file-upload/server/content/files/160828c7200e1c---wafimogoxu.pdfIn PDF document text
    • http://glassco.ca/clients/9/99/99aa1728c1dafa3cf8773a75727b87c9/File/37619588090.pdfIn PDF document text
    • http://villaturri.it/wp-content/plugins/formcraft/file-upload/server/content/files/161239cbf02dd1---wanomavevewoxarojarebexe.pdfIn PDF document text
    • http://2478.ru/admin/ckfinder/userfiles/files/25285202039.pdfIn PDF document text
    • https://serka.com/serka/upload/files/dotizolumawuzo.pdfIn PDF document text
    • http://s4l.vn/storage/ckfinder/files/51024477502.pdfIn PDF document text
    • http://inwallendorf.de/userfiles/file/53256539758.pdfIn PDF document text
    • https://kes-stv.ru/wp-content/plugins/super-forms/uploads/php/files/830c20e6c184d8c383bfe1e945501274/72111871474.pdfIn PDF document text
    • https://brtim.com/uploads/wysiwyg/files/tapotan.pdfIn PDF document text
    • http://baanpowertrain.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f2ef3f527bd---48865986894.pdfIn PDF document text
    • https://chachachat.info/js/ckfinder/userfiles/files/zeruzebisunateze.pdfIn PDF document text
    • http://amctop.com/board_data/editor_img/file/202106111219.pdfIn PDF document text
    • http://taxicityplus.ru/userfiles/file/wuvitifuwenow.pdfIn PDF document text
    • http://elite-weekend.com/clients/9/94/945a7f92a07ecc721aac768ad340748a/File/fodomev.pdfIn PDF document text
    • http://keystoparadise.com/userfiles/files/99740869475.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=singular+plural+nouns+rules+worksheetPDF 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_off0000c87f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC87F 10884 bytes
SHA-256: d2be06e30659fc2c5cb53d4dbf106efc164d30ddf1bd690c174e5183acadc964
font_01_sfnt_off0000e1a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1A8 17604 bytes
SHA-256: fc1ad320d323e033f2c4f58e960b03d623cb990198fff379c6b7481435ded6dc
font_02_sfnt_off00010ed9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10ED9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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