Malicious PDF — malware analysis report

Static analysis result for SHA-256 66888ff9800e5219…

MALICIOUS

PDF

80.0 KB Created: 2021-09-06 23:53:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: e9a7f27edde264680b3f175e920e8c51 SHA-1: 32310f06cb265dcc5f8271d5ee58e22c0e6ff208 SHA-256: 66888ff9800e52192d64c62f1bd2794dc44cccc66d0037535a8733cadfb93f78
156 Risk Score

Malware Insights

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

The PDF contains numerous external URIs and link farm heuristics, indicating its primary purpose is to redirect users to potentially malicious websites. The ClamAV detection and ML classifier strongly suggest malicious intent, likely for phishing or malware distribution. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but reinforcing the file's nature as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://krisoc.ru/uplcv?utm_term=matura+angielski+%C4%87wiczenia+gramatyczne+pdf PDF link annotation
    • http://dungcumaymoc.com/Images_upload/files/13161011849.pdfIn PDF document text
    • http://joshuadacosta.com/wp-content/plugins/formcraft/file-upload/server/content/files/16121713040d65---69159317225.pdfIn PDF document text
    • https://www.entornopublicitario.com/wp-content/plugins/super-forms/uploads/php/files/6db8964346488b29573b68443eb38da2/wivumofokopoxozafukuwulo.pdfIn PDF document text
    • https://dm288.rs/slicice/file/78409755383.pdfIn PDF document text
    • https://turbooto.vn/upload/files/nilenevevimix.pdfIn PDF document text
    • http://washchienluoc.com/upload/file/duxami.pdfIn PDF document text
    • https://asset-books.com/userfiles/file/texulusadokobul.pdfIn PDF document text
    • https://www.tessilgiada.it/wp-content/plugins/formcraft/file-upload/server/content/files/1609f1b42d2502---kebasetoduzusadaluxefefe.pdfIn PDF document text
    • https://antae.be/app/webroot/uploads/file/sepixexegovibababuniwavi.pdfIn PDF document text
    • http://tuecpa.com/file_media/file_image/file/likawokuf.pdfIn PDF document text
    • http://ahxxzx.com/userfiles/202105/file/21925754875.pdfIn PDF document text
    • https://firsatpin.com/calisma2/files/uploads/32742212046.pdfIn PDF document text
    • http://demirlermetal.com/resimler/files/fabuwosajulovitonej.pdfIn PDF document text
    • http://studioindelicato.com/userfiles/files/12062280714.pdfIn PDF document text
    • https://foulardfotografando.it/file/23728010821.pdfIn PDF document text
    • http://boulderdivorcelaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e8f3c59c98d---xijikijiza.pdfIn PDF document text
    • https://calprin.com/ckfinder/userfiles/files/16647472783.pdfIn PDF document text
    • http://capthepcongtrinh.com/uploads/news/files/19590265401.pdfIn PDF document text
    • https://regionalhealthprogramsww.com/images/file/59700456012.pdfIn PDF document text
    • http://esebtekstil.com/resimler/files/bojodokinakemutix.pdfIn PDF document text
    • http://hoteldanang.com/uploads/images/files/9822212640.pdfIn PDF document text
    • http://erbilsunhotel.com/wp-content/plugins/super-forms/uploads/php/files/sog2u0s06bj8cq22tv4lrae1j7/degumuwewizix.pdfIn PDF document text
    • https://letstravelforacause.com/miet/assets/files/fazivusonijusawupijo.pdfIn PDF document text
    • https://yalcinplayer.com/calisma2/files/uploads/9170382146.pdfIn PDF document text
    • 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_off0000cda2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDA2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e5b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5B9 11424 bytes
SHA-256: 15439de3091827a39f0630e3603de71ce3accbd8f5e3b37c3adb5d97f3db9019
font_02_sfnt_off0001004d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1004D 19136 bytes
SHA-256: aedfef1bf503a447f0eafff72f722cf19bc04bc2cfa203d5c5b0b5ddeeda56fa

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