Malicious PDF — malware analysis report

Static analysis result for SHA-256 21f33379117425de…

MALICIOUS

PDF

86.6 KB Created: 2021-09-06 14:53:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 9581e52ba1c76798af6f02f75af0271f SHA-1: c6273c4c81f39bb7eb77cf55c7a6f4ec88cad82f SHA-256: 21f33379117425de8de92d78b3e5c95bde989da823d274106127eea5dc1831de
164 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript and numerous external URIs, many pointing to compromised WordPress sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. The embedded JavaScript is likely responsible for redirecting the user to malicious sites, as suggested by the PDF_JS heuristic.

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.
  • 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://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160773185d03e1---gadarubumudedimaju.pdf In PDF document text
    • http://waterreducer.cn/d/files/33154508912.pdfIn PDF document text
    • https://mvmdigital.gr/files/files/54578149159.pdfIn PDF document text
    • http://gapoom.com/upload/fckeditor/file/74584015490.pdfIn PDF document text
    • http://chargers68-50th.com/clients/3/3d/3dd154274af4887fbe356f6dcfc18689/File/tetufedekiboledug.pdfIn PDF document text
    • http://giftboxvietthuy.com/upload/ck/files/90531289587.pdfIn PDF document text
    • http://burningspearmarketplace.com/js/ckfinder/userfiles/files/wufamosogaremogitu.pdfIn PDF document text
    • http://www.iamgoingto1996.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c567b6727d8---nigerumer.pdfIn PDF document text
    • http://mko-yug.ru/wp-content/plugins/super-forms/uploads/php/files/fd36c16f632ea860053f7f8f2f5ccb44/lasevinow.pdfIn PDF document text
    • http://www.juniorcollege.cl/ckfinder/userfiles/files/50308154209.pdfIn PDF document text
    • http://flirdining.com/uploads/files/37857730057.pdfIn PDF document text
    • https://siyata.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/160d49db48bf1f---kosiwolu.pdfIn PDF document text
    • http://to-kajihan.net/js/upload/files/63906704767.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ab650495fa---14070214742.pdfIn PDF document text
    • http://clinivetmadonnadirosa.eu/userfiles/files/tulerebadodavidi.pdfIn PDF document text
    • https://wurstfargo.com/wp-content/plugins/super-forms/uploads/php/files/b249a877d8456a7c8c71928839c01305/sofok.pdfIn PDF document text
    • http://xn--b1akwe.xn--p1ai/userfiles/file/81031269042.pdfIn PDF document text
    • https://facades-et-traditions.com/actualites/file/batozufarekuzujipa.pdfIn PDF document text
    • https://master.plus/wp-content/plugins/super-forms/uploads/php/files/ed083df54d1a0bc910839603c45d4479/72936954959.pdfIn PDF document text
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bee01f96cff---sigukesuwumi.pdfIn PDF document text
    • https://414movement.com/wp-content/plugins/super-forms/uploads/php/files/d781d60ad4ca3f7ed4a24f06f7e0af97/15981084100.pdfIn PDF document text
    • https://f1com.ge/wp-content/plugins/super-forms/uploads/php/files/bde972f8aa29723f967574b1955d8ef8/pokow.pdfIn PDF document text
    • https://sealskinz.ru/files/file/sivubulana.pdfIn PDF document text
    • http://eastendmediation.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/gojonogavegut.pdfIn PDF document text
    • https://www.opdrrustukalac.com/wp-content/plugins/formcraft/file-upload/server/content/files/16100e0cf379d5---rumojarekimaxewawiduvawuv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=fusionner+des+document+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_off0000ec1b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC1B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010432.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10432 10652 bytes
SHA-256: b43d99a068af801241b51376d1c51a9d005680d08e4cf91a5bbe02bb51c8dd1d
font_02_sfnt_off00011c89.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C89 19200 bytes
SHA-256: 86d952d6c1439ce7fac2ca08a543f3d91d4495213ce0a79109f82883b904c903

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