Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f3b5131fe27204…

MALICIOUS

PDF

84.5 KB Created: 2021-09-06 18:54:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 16cb24a2ac875ee2e0118b6b1367e7af SHA-1: a9a1d5be343bb0f4ae57529eb03cea5550b6f988 SHA-256: 81f3b5131fe272042fa7badbcfb83af0792dab677785314995113e5a6b4e3ed3
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, directing users to compromised WordPress sites hosting PDF files, which likely serve as lures for phishing or malware distribution. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://vashadvokat82.ru/wp-content/plugins/super-forms/uploads/php/files/07daf5b0e6c8df1ff74e59ba6d9f00a1/3814602055.pdf In PDF document text
    • http://waltonjohnsonfamily.com/clients/870437/File/mabuvenojupox.pdfIn PDF document text
    • http://www.restorationservice.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160d4e4f9cf6a7---mabejirefixadan.pdfIn PDF document text
    • http://woodwork.pl/ubezpiecz/obrazy/file/53872877502.pdfIn PDF document text
    • http://www.alfapilates.pl/upload/file/muvupoje.pdfIn PDF document text
    • https://goldengrowers.com/wp-content/plugins/super-forms/uploads/php/files/4b5a8cb551876ded892343e391b347da/86057648629.pdfIn PDF document text
    • http://smartarts.bg/userfiles/file/mawodurarelo.pdfIn PDF document text
    • http://www.temaricerca.com/entry2013/admin/ckfinder/userfiles/files/bixinisunexegozemo.pdfIn PDF document text
    • https://fajanav.com/aym_image/files/46824946791.pdfIn PDF document text
    • http://amoy-art.com/Upload/file/fevijirel.pdfIn PDF document text
    • http://www.adatechotomasyon.net/wp-content/plugins/formcraft/file-upload/server/content/files/1606efd63a194e---milopefekinakebikozodajo.pdfIn PDF document text
    • http://inter-travel.hu/_user/file/wewixokebafetalepejo.pdfIn PDF document text
    • http://fashioncenterpoint.com/wp-content/plugins/super-forms/uploads/php/files/813431169155bd0a6b6a2c74e2626bd7/94549169749.pdfIn PDF document text
    • http://smart.sut.ac.th/tsme/src/lib/ckfinder/userfiles/files/gevuralasemoputezenasu.pdfIn PDF document text
    • http://clinicaveterinariamontecchia.com/userfiles/files/51212782957.pdfIn PDF document text
    • http://hevolta.com/upload/file/87012067962.pdfIn PDF document text
    • http://webursitet.org/Files/file/juwomilafexuxexivorilapo.pdfIn PDF document text
    • http://asianaccounting.com/admin/fckeditor/userfiles/file/beviju.pdfIn PDF document text
    • https://seo-methodes.com/userfiles/file/zaxevu.pdfIn PDF document text
    • http://betamarin.com/images/media/files/30283752613.pdfIn PDF document text
    • http://www.nationaalgolfcongres.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16094c2c27fc13---79522220136.pdfIn PDF document text
    • https://www.webhisto.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16098784be4484---reledesozinixudobap.pdfIn PDF document text
    • http://sea-cruise.ru/ckfinder/userfiles/files/40422873164.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=basic+civil+engineering+viva+questions+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_off0000e396.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE396 17968 bytes
SHA-256: 598b2135d74da891271558a18be3c1a0231a358b6a6e02640ef91ea026226774
font_01_sfnt_off0001127d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1127D 11160 bytes
SHA-256: 2b04ffebab65dc9dc1495925c91af3a6adc4848753a10f6441c2637d765c64dc
font_02_sfnt_off00012c3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C3A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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