Malicious PDF — malware analysis report

Static analysis result for SHA-256 636a62d1679aae54…

MALICIOUS

PDF

86.4 KB Created: 2021-08-13 10:01:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 18a229f4c6f352d70b676f6606ab39ab SHA-1: e0a05a07d5d59f5f9ea6fa63d2fe7b65a743bae3 SHA-256: 636a62d1679aae540e2b382338df5e51c419f86718e1e5a0bc57a8bfde94d55b
156 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It functions as a link farm, with numerous URLs pointing to compromised WordPress sites, likely serving as a distribution point for further malicious content. The document body is heavily obfuscated and appears to be metadata from the wkhtmltopdf tool, offering no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9970

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://www.bouwenaaneensterkwerkgeversmerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1610a1c317e662---podijogekowe.pdf In PDF document text
    • https://paloaltospeakerseries.com/wp-content/plugins/super-forms/uploads/php/files/dd544966f575fdeabcab681396a7a907/sitejifotelevazajenejala.pdfIn PDF document text
    • http://niestachow.pl/data/aktualnosci_imgs/file/rusuw.pdfIn PDF document text
    • http://pechati-piter.ru/userfiles/file/92987575399.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/dc916323f3782468e7d4600f497c7cbb/kilejoxikelonobixota.pdfIn PDF document text
    • https://guptajimarriagebureau.com/userfiles/file/76397687953.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1608aa43eb1afa---pidogalepanivifevat.pdfIn PDF document text
    • http://at2apigroup3.com/contents//files/36397888582.pdfIn PDF document text
    • http://elenasteele.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607391be37757---lepipixox.pdfIn PDF document text
    • http://kaupa.cz/userfiles/file/kosob.pdfIn PDF document text
    • http://paroissedementon.fr/upload/files/losigosisijo.pdfIn PDF document text
    • http://fortlauderdalelimorental.net/wp-content/plugins/formcraft/file-upload/server/content/files/160e89bfa2b0a0---xupumipidisur.pdfIn PDF document text
    • https://bonacorsi.it/file/47645490107.pdfIn PDF document text
    • http://saamfactory.com/wp-content/plugins/super-forms/uploads/php/files/77f508bdd77e31d53d9475bc000eee35/naxorixasakerunap.pdfIn PDF document text
    • https://www.projectorrentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2f56e49c91---99299970776.pdfIn PDF document text
    • https://krimgranit.ru/wp-content/plugins/super-forms/uploads/php/files/170d92a1bf1a1ebca5e60f268a6d03f2/41849884655.pdfIn PDF document text
    • https://1sis.com/wp-content/plugins/formcraft/file-upload/server/content/files/160901a6a74c54---waxudise.pdfIn PDF document text
    • https://xn--p3t29jo1ed4o4xw.tw/upload/files/jobejusal.pdfIn PDF document text
    • http://gps-tw.com/CKEdit/upload/files/49924995920.pdfIn PDF document text
    • https://chamsocmuihong.com/wp-content/plugins/super-forms/uploads/php/files/fetaohov73d539r3mdaq15djcb/37006405456.pdfIn PDF document text
    • https://activepymes.com/pub/file/jetikuwo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=king+of+fighters+2002+magic+plus+2+androidPDF 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_off0000ee00.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE00 11400 bytes
SHA-256: e22772c608a63540e167c9623fa78cfdd856aec47bd85d5acebe6cfa99941092
font_01_sfnt_off0001087b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1087B 16844 bytes
SHA-256: 5c15eff49b60905cc6afd8864d7c6cab1654b04fbf12d4025f5b57916a9b0499
font_02_sfnt_off00013438.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13438 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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