Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c28f99b28dbd08b…

MALICIOUS

PDF

72.6 KB Created: 2021-06-18 23:06:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-12
MD5: 2a005205e6f61bbace493122c7faf28f SHA-1: 5d5bd49ecd5daa6f18bb20d29c8cd09a68d6ac0b SHA-256: 5c28f99b28dbd08b769653b1007a728fd0775f8c2b90a2d146f7db0ccca374ac
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a link farm pointing to multiple compromised WordPress sites, suggesting an attempt to distribute malicious content or phish users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, lacking clear user-facing text but containing metadata that aligns with the link farm heuristic.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://monacollection.ua/wp-content/plugins/super-forms/uploads/php/files/b0c4c6f44480b946fa3896a7bbd9f200/51800834685.pdf In PDF document text
    • https://www.servicioscalibrados.com/wp-content/plugins/super-forms/uploads/php/files/1a5c8d5690f2c7edf3528c30edae9cb2/62606795463.pdfIn PDF document text
    • http://ctkupavna.ru/upload/file/rerisarigejanexuwota.pdfIn PDF document text
    • http://bridgesonthepark.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607812bc1d951---89718865212.pdfIn PDF document text
    • http://botanicgardenscafe.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160c6e986c5df2---xedulogedesoxafewokig.pdfIn PDF document text
    • http://bilagroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bf41ed619ea---14382357422.pdfIn PDF document text
    • https://www.lightingdynamics.com/wp-content/plugins/super-forms/uploads/php/files/805792dcc6e0ff9530962a234f35b758/vikukitumiwapalon.pdfIn PDF document text
    • https://www.groupenahno.com/wp-content/plugins/super-forms/uploads/php/files/ee4h546eg2sng57kfn0jk1qe7k/jivozexagorab.pdfIn PDF document text
    • http://andlupa.com/userfiles/file/kotikopenudozitigoz.pdfIn PDF document text
    • https://www.drserapkagan.com/wp-content/plugins/super-forms/uploads/php/files/gf5hpemue12smfvkjm40hvgjte/xegujogakenitejo.pdfIn PDF document text
    • http://www.myhhsi.com/wp-content/plugins/super-forms/uploads/php/files/28387b527d776131a673d2a3f6f150a6/fizeminomepapinimoda.pdfIn PDF document text
    • https://sambelteri.com/contents//files/67324269287.pdfIn PDF document text
    • https://www.helpagesl.org/wp-content/plugins/formcraft/file-upload/server/content/files/16087f51640515---veraluruxinizazajipuneju.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=municipal+solid+waste+management+lecture+notesPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ce8e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE8E 5372 bytes
SHA-256: ed71bd4ddda32f6a5e34f33f43a74ebb7f8c33dd0ac69c851f50a2e874e2b52d
font_01_sfnt_off0000e0cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0CB 11284 bytes
SHA-256: df26e9d16cb030063107458f973d546a22141bbd26105545a78f56654403156a
font_02_sfnt_off00010726.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10726 4324 bytes
SHA-256: ff5f0ef16caf3e97cd1984b3a03ea88e11eab8cf63d2ee006085a4b9995833f3