Malicious PDF — malware analysis report

Static analysis result for SHA-256 b731441c63535133…

MALICIOUS

PDF

68.5 KB Created: 2021-10-03 01:21:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 28f4e48355a63eedc793a5919bd81c5c SHA-1: 4ab1686380571d9483267a427bb3fc3f50735c05 SHA-256: b731441c6353513316524357f39101c2788090f9b23fb50b0e65a41ea4904ebb
156 Risk Score

Malware Insights

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

This PDF file was identified as malicious by a machine learning classifier and ClamAV. It functions as a link farm, containing numerous URLs pointing to compromised CMS uploads and disposable hosting. The primary goal appears to be redirecting users to external sites, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9986

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 http://siblom.ru/files/upload/file/38159639893.pdf In PDF document text
    • http://ac-kenigsberg.ru/files/file/38522245508.pdfIn PDF document text
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/1612ef6e3f0369---46577639236.pdfIn PDF document text
    • http://www.absolutecateringla.com/wp-content/plugins/formcraft/file-upload/server/content/files/161373bd972553---dulokitogutonamokubojud.pdfIn PDF document text
    • https://pioneerlift.com/upfiles/editor/files/91320452738.pdfIn PDF document text
    • http://investin-khj.ir/ckfinder/userfiles/files/bagotixajolivure.pdfIn PDF document text
    • http://stl-hk.net/userfiles/vevaluzononewejiwozumaruf.pdfIn PDF document text
    • http://av-jet.ru/userfiles/file/55099866378.pdfIn PDF document text
    • https://hockeymro.ca/docs/file/78455501087.pdfIn PDF document text
    • https://prana.video/wp-content/plugins/super-forms/uploads/php/files/p3mi95jifqr5nst89g7ast9e0o/30788637405.pdfIn PDF document text
    • http://gordostcrista.ru/userfiles/file/gogojamefelomegijube.pdfIn PDF document text
    • http://halkum.rs/files/totixowedijozobisilosasej.pdfIn PDF document text
    • https://rjpexport.com/files/litulax.pdfIn PDF document text
    • https://prestinireedcorp.com/userfiles/files/rigefejuzuxikepamewuf.pdfIn PDF document text
    • https://xn--90aoja6ahg5ds.xn--p1ai/uploads/files/15626823553.pdfIn PDF document text
    • http://letsfinal.com/userfiles/file/3736566009.pdfIn PDF document text
    • http://fandimnarodaku.cz/upload/file/saxepinojupuzezipapinape.pdfIn PDF document text
    • http://hemeringen.de/ckeditor_ablage/userfiles/files/vebudapaxapamoxevixixe.pdfIn PDF document text
    • http://www.studiolegalefusimorelli.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614208f660803---89909061425.pdfIn PDF document text
    • http://market-oborudovanie.ru/upload/file/selis.pdfIn PDF document text
    • http://velapower.com/glwh/UploadFile/file/2021092713295273499.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=time+series+databases+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_off0000ad77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAD77 10492 bytes
SHA-256: 05252983605dfe989ab181c960f390b77c9e97a3f2087b31965cefbf8f671e15
font_01_sfnt_off0000c516.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC516 15140 bytes
SHA-256: 72fac449778f9c5a020756690ad8b7e5d2060999efb83765413e9802dfd25925
font_02_sfnt_off0000eaf6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAF6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1