Malicious PDF — malware analysis report

Static analysis result for SHA-256 cd9d7c79189783c6…

MALICIOUS

PDF

83.8 KB Created: 2021-09-10 12:12:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 5dc33ffd20582e3c8e05f8fb635cc672 SHA-1: 779b1395a2c8fbcaa34f2428d809181d70d1e9d4 SHA-256: cd9d7c79189783c68ab7899898ad1f320230b6cd82a988ab0c4d04c2dda42060
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it's a link farm pointing to compromised WordPress uploads and disposable hosting. The embedded URLs, such as https://laborke.ru/uplcv?utm_term=slaughterhouse+five+free+pdf, are likely used to redirect users to phishing sites or download further malicious content. The PDF structure itself is also noted for object duplication, suggesting manipulation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://laborke.ru/uplcv?utm_term=slaughterhouse+five+free+pdf PDF link annotation
    • http://dnepropress.net/files/file/27715074437.pdfIn PDF document text
    • http://honmamon-s.com/img_seminar/userfiles/file/wogebolekobazu.pdfIn PDF document text
    • https://torbay.ru/images/uploads/file/fokevedado.pdfIn PDF document text
    • http://7seapharmtech.com/Uploadfiles/files/wenowekum.pdfIn PDF document text
    • https://almuhja.ps/ckfinder/userfiles/files/kenavawazagogasom.pdfIn PDF document text
    • https://www.passion-rnd.com/upfile/files/2021/09/09/wewofi.pdfIn PDF document text
    • https://bestofbucerias.com/upload/file/navulubelobuvujiwi.pdfIn PDF document text
    • http://cp-tournament.org/ckfinder/userfiles/files/wafebezitibere.pdfIn PDF document text
    • https://kingyao.com/uploadfiles/files/20210909_200048_4083.pdfIn PDF document text
    • http://cementfeet.com/userfiles/file/20494188190.pdfIn PDF document text
    • http://amexeuro.com/an3_Uploads/file/powome.pdfIn PDF document text
    • http://stolizstekla.ru/userfiles/file/5739306192.pdfIn PDF document text
    • https://propbrains.com/wp-content/plugins/super-forms/uploads/php/files/58f0082567ea1ef29c8a5073795c83e3/86960581063.pdfIn PDF document text
    • http://eva.am/files/1d84fc7185492e73.pdfIn PDF document text
    • http://xn--90afqerdlt1f.xn--p1ai/admin/ckfinder/userfiles/files/jotelepu.pdfIn PDF document text
    • https://asmitahrgroup.com/ckfinder/userfiles/files/pexolemigo.pdfIn PDF document text
    • http://lejuriste.ru/files/file/vikenefogometopelisu.pdfIn PDF document text
    • http://camel-republic.com/media/userfiles/files/25481068131.pdfIn PDF document text
    • http://mstreatmentadvances.com/userfiles/files/33197179058.pdfIn PDF document text
    • https://gkia.org/kingkong/userfiles/files/fivopemegine.pdfIn PDF document text
    • http://asremajazi.com/uploads/files/89112328266.pdfIn PDF document text
    • https://glosunspa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613115ecf2370---gubipokogabokupubot.pdfIn PDF document text
    • https://www.hosotte.com/ckfinder/userfiles/files/zugulavadavimonogusidi.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/161361d3a45dc1---62613647594.pdfIn PDF document text
    • https://djennebeads.com/nbloom/fckuploads/file/pafeligawogewos.pdfIn PDF document text
    • http://www.libroparlatolions.it/backoffice/ckfinder/userfiles/files/rukivasikatipufuwefit.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_off0000e13e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE13E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f955.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF955 10916 bytes
SHA-256: d7262c0433590f034a424847f015b27ca819595ec89c9ea87e0fe6c504ea8957
font_02_sfnt_off00011287.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11287 18024 bytes
SHA-256: 79a3a14a65ab4fb58c58c8129dacfebd77e6b31cfa0ae8de4040c3bfa784c529