Malicious PDF — malware analysis report

Static analysis result for SHA-256 7d8923de5519d754…

MALICIOUS

PDF

90.0 KB Created: 2021-08-10 11:46:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 3dee3ef9b19ce0366cd37c07961ec27c SHA-1: 03d81e664751dd6d95c62646cc886a4f460305b7 SHA-256: 7d8923de5519d754667014b807e76f59427eb527ebc514e1221224a31d412960
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, specifically identified as a phishing trojan by ClamAV. It contains a large number of embedded URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to phishing or malicious content. The authoring application 'wkhtmltopdf' is also noted, which can be used to generate PDFs from web content, further supporting the phishing lure hypothesis.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://crysiq.ru/uplcv?utm_term=suma+y+resta+de+fracciones+homog%C3%A9neas+ejercicios+resueltos PDF link annotation
    • http://machinegroup.ru/img/outer/files/2638273079.pdfIn PDF document text
    • http://runo34.ru/attachments/file/6753279093.pdfIn PDF document text
    • http://presssimayeshahr.ir/pic/file/13616864346.pdfIn PDF document text
    • http://cosyromania.com/media/file/zugaxowinuwusal.pdfIn PDF document text
    • https://galerie-louise.be/userfiles/files/wetesinago.pdfIn PDF document text
    • https://gulertrafik.com/wp-content/plugins/super-forms/uploads/php/files/4g82seh4pdcg7ibognokrtjlrq/10900024872.pdfIn PDF document text
    • http://pratiklinik.com/img/userfiles/files/29034060038.pdfIn PDF document text
    • https://medok18.ru/wp-content/plugins/super-forms/uploads/php/files/65e1208977d3728f9f0fbd1963e9d2c9/zoliguxitigazisutikusezi.pdfIn PDF document text
    • https://etre-cheval.fr/Applications/MAMP/htdocs/etre%20cheval/news_pix/file/65569122999.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608139036ade6---301641487.pdfIn PDF document text
    • http://cageart.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1607e458380a80---xeronusujixiloxu.pdfIn PDF document text
    • https://argumentua.com/i/file/42581884590.pdfIn PDF document text
    • https://www.vibrationmonitoring.asia/wp-content/plugins/formcraft/file-upload/server/content/files/16109058e491bd---54446101938.pdfIn PDF document text
    • http://retrievers.su/ckfinder/userfiles/files/62212528740.pdfIn PDF document text
    • http://xn--o79av69abka850ab6c.com/upload/file/202105281348090733.pdfIn PDF document text
    • https://www.popcaffe.it/wp-content/plugins/super-forms/uploads/php/files/17116adf994075ef0ef535651f704107/28982356501.pdfIn PDF document text
    • https://leo-translate.com.ua/wp-content/plugins/formcraft/file-upload/server/content/files/1608181e3acc60---kiketidowomivanug.pdfIn PDF document text
    • https://hssipm.com/wp-content/plugins/super-forms/uploads/php/files/041d4659f2a6f541745ad2ab3a4056e9/66370865974.pdfIn PDF document text
    • http://www.garriagricola.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094ccd8c70c8---pixiperonu.pdfIn PDF document text
    • http://elma-itc.ru/!upload/files/95286218039.pdfIn PDF document text
    • https://g3az.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d4fa6ad5fe---5799081631.pdfIn PDF document text
    • https://stijsr.com/userfiles/file/82243702425.pdfIn PDF document text
    • http://446888.top/userfiles/file/puvotaxopoveba.pdfIn PDF document text
    • http://xn--h1aeekk.xn--p1ai/files/file/mezulidabebona.pdfIn PDF document text
    • http://xn--80aikni6a0b.xn--p1ai/images/file/66139735429.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_off0000f546.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF546 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010d5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D5D 11496 bytes
SHA-256: 4f931d0563070784ffb2cd664099ee188d9a48bc971b65dfdddc6d720e1ea45a
font_02_sfnt_off000127da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x127DA 18448 bytes
SHA-256: 0414f007103eb156243047b9b2a6ee578830c57d1f692e5001806890a107dec1