Malicious PDF — malware analysis report

Static analysis result for SHA-256 a31103bbff525bf9…

MALICIOUS

PDF

67.5 KB Created: 2021-06-07 03:35:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: f52370f44b23c280deb68ab1cf7ded90 SHA-1: ef0fdd49254578ff71f86c87992e3aa15c761637 SHA-256: a31103bbff525bf9e2016ed55b3fc2ac61bf1d76c02fb08260f4648cf37a4a5b
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, with ClamAV identifying it as a phishing trojan. The document contains a large number of embedded URLs, many of which point to compromised WordPress sites and disposable hosting, suggesting a link farm designed to redirect users to malicious content. The primary attack pattern involves leveraging these links for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://oniceh.ru/uplcv?utm_term=us+army+bases+in+germany+1960s PDF link annotation
    • http://osullivanspressurewashing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085e291c35a9---82877091732.pdfIn PDF document text
    • http://joshuadacosta.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a8cfdbf0b2b---99063655926.pdfIn PDF document text
    • http://facilitymanagementassociates.com/survey/userfiles/files/92210997477.pdfIn PDF document text
    • http://barrarioservicos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609f5bdbc495c---maxesed.pdfIn PDF document text
    • http://ahlhy.com/uploads/file/292143468281.pdfIn PDF document text
    • https://lightingsystemscol.com/wp-content/plugins/super-forms/uploads/php/files/ba447263626848731ad64713bf8b5c00/18287590338.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/160ac36b9ab331---jonuxogetedibuxovijob.pdfIn PDF document text
    • http://www.combatsim.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16078586834268---86870659413.pdfIn PDF document text
    • https://tirthmobile.com/wp-content/plugins/super-forms/uploads/php/files/jmbc6cjat0grm395dv3mfssju6/nuxosejafekipirusuke.pdfIn PDF document text
    • https://alllegaltask.com/wp-content/plugins/super-forms/uploads/php/files/qlkc695ebrlt5b7ififr3ng1vs/dawejofe.pdfIn PDF document text
    • https://buddingheights.org/wp-content/plugins/formcraft/file-upload/server/content/files/1608e3347c928d---mulutefexej.pdfIn PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/o0mj41r8q4pttejk2nahvaoqg3/91770228218.pdfIn PDF document text
    • https://mymovingestimate.com/wp-content/plugins/super-forms/uploads/php/files/36e0a8e4d75eb28d4617d27355cd3a1c/29780724000.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cc07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC07 5708 bytes
SHA-256: 9d4361025fcfb7a9af17e64669921b4c027b35ae5f3a5d23c96b1a20b902c645
font_01_sfnt_off0000df68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF68 10196 bytes
SHA-256: c68ef00db7408de8cefa770c4a0e274c2f316e479722d13daa5ad8c174ee975c

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