Malicious PDF — malware analysis report

Static analysis result for SHA-256 104e76821f7af229…

MALICIOUS

PDF

82.6 KB Created: 2021-09-05 03:05:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: b13e10c12f4b49f87cfa8049544ccd63 SHA-1: 9130098f44db6f8baac95c195a0ea0ac8a9fb811 SHA-256: 104e76821f7af229e57f44e996f1cdcf0718803cebd861234ef1eceae67b62ef
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by a machine learning classifier and ClamAV, indicating a high likelihood of malicious intent. It contains numerous links, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, further supporting the idea that the document's primary function is to host these malicious links rather than convey information.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://www.mecateengenharia.com.br/ckfinder/userfiles/files/vunexajedavole.pdf In PDF document text
    • https://edukiya.com/wp-content/plugins/super-forms/uploads/php/files/985454059e126934a0bd4fa2a3141d69/10043777329.pdfIn PDF document text
    • http://metabolit-plus.ru/files/file/xowejirogetuw.pdfIn PDF document text
    • https://www.caesarstravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160824c9a20a27---34486460297.pdfIn PDF document text
    • https://bmat.mn/uploads/ckfinder/files/91694399592.pdfIn PDF document text
    • https://cristiandellavedova.com/wp-content/plugins/super-forms/uploads/php/files/v46at1kb4fbg5ghdsgk37esrv3/70305993552.pdfIn PDF document text
    • https://noithatkuongthinh.com/uploads/files/botujidejerupulokamenexan.pdfIn PDF document text
    • https://prosegik.com/wp-content/plugins/super-forms/uploads/php/files/cd3d48e3ea4bd1f4d7ad78a8358962e8/fujiwidog.pdfIn PDF document text
    • https://sunnyrosesschool.com/userfiles/file/mugilirimavubexijuzaxog.pdfIn PDF document text
    • http://akicgiyim.com/userfiles/file/62563770.pdfIn PDF document text
    • https://alianzatours.com/imagenes/file/68753719623.pdfIn PDF document text
    • http://entryexpress.online/chapter_images/files/30377533831.pdfIn PDF document text
    • http://aceonlinementors.com/userfiles/file/79617255603.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/5142e79a83a1dd2e309e242cf5be7978/jukifonalasumu.pdfIn PDF document text
    • http://flamefitnessstudio.com/cewit/images/file/52485242247.pdfIn PDF document text
    • https://ketex.com/trcgp/ckfinder/userfiles/files/mebosex.pdfIn PDF document text
    • http://altelaw.com/uploads/image/file/fivikepitukili.pdfIn PDF document text
    • http://eastindiaspray.com/suvra/eastindia_spray/files/30968257295.pdfIn PDF document text
    • http://all-pass.com/folder/editor/file/gowanezasisi.pdfIn PDF document text
    • http://www.louthadventures.ie/wp-content/plugins/formcraft/file-upload/server/content/files/1608d3c423d8f6---18888852012.pdfIn PDF document text
    • https://rhdplumbing.com/wp-content/plugins/super-forms/uploads/php/files/029a5ba87ae466753c136ac85d09143e/63764503136.pdfIn PDF document text
    • https://allcreaturesinc.com/files/files/jidaramoje.pdfIn PDF document text
    • https://infoenergie-loire.org/userfiles/file/98096487848.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=kuk+revaluation+result+2017+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_off0000db39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB39 11084 bytes
SHA-256: f93d72065ed46886cd62358df9c32ca2e6e9acf89fa6174f12e651ea0e627b8c
font_01_sfnt_off0000f553.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF553 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010d65.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D65 18232 bytes
SHA-256: 1d7715ee26208151b6d0fe72f50eb5902eea89645b8cee21a1911b1cf58e1548

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