Malicious PDF — malware analysis report

Static analysis result for SHA-256 81979cbeb6dae198…

MALICIOUS

PDF

81.8 KB Created: 2021-06-24 11:30:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: dc4424c26206c7d79699f115c8582e76 SHA-1: cb695909a4fe80a703cab92d925d6258d6fa3349 SHA-256: 81979cbeb6dae19853e769618b331518858bb416f4fc4aa8bfc7b625191faa18
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous embedded links, many pointing to compromised WordPress sites, suggesting a phishing or malware distribution attempt. The ClamAV detection and ML classifier strongly indicate malicious intent. While no scripts were explicitly extracted, the presence of external URIs and link farms points to the likely execution of JavaScript or other embedded content to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://inwebjor.ru/uplcv?utm_term=std+11+english+book PDF link annotation
    • https://drainscovers.com/wp-content/plugins/super-forms/uploads/php/files/8e592164a5502135f9c4d384d2c948ca/48347898521.pdfIn PDF document text
    • http://www.redactordecontenidos.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16079067264258---zekulezununabutab.pdfIn PDF document text
    • https://arnetbilgisayar.com/upload/ckfinder/files/razukudotuvojagadunopeda.pdfIn PDF document text
    • https://deewo.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a9bde7e56a7---81987179113.pdfIn PDF document text
    • http://bularz-auto.pl/images/userfiles/file/78946439297.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/e51bbd2495d8258d7e2845c916bb8760/wejujoz.pdfIn PDF document text
    • http://doublehappyvstheinfinitesadness.com/wp-content/plugins/formcraft/file-upload/server/content/files/160946c9fc5692---69584821539.pdfIn PDF document text
    • https://indacphuc.com/wp-content/plugins/super-forms/uploads/php/files/cs87f82972jd8c0257edpra1fn/kiwuvumukabe.pdfIn PDF document text
    • https://parfumzone.ro/files/file/33892644656.pdfIn PDF document text
    • https://www.ezhealthcheck.com/wp-content/plugins/super-forms/uploads/php/files/88lt2eucbov6aohom9effg129f/kumozo.pdfIn PDF document text
    • https://gastrotest.co/ckfinder/userfiles/files/redikigabazurenar.pdfIn PDF document text
    • http://makaeximworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606e0c3321528---rekuguzo.pdfIn PDF document text
    • https://www.ideaklinik.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160d1faac83637---16457884923.pdfIn PDF document text
    • https://www.wikiwebagency.it/wp-content/plugins/super-forms/uploads/php/files/870419b52496ea4c8da924ed1c8c49dc/79180321849.pdfIn PDF document text
    • https://www.alarisusallc.com/wp-content/plugins/super-forms/uploads/php/files/e24a2a8b96e1158aed406c1c04a52f10/dusin.pdfIn PDF document text
    • http://serendipityorlando.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071c32955af5---28085406846.pdfIn PDF document text
    • http://fedorahosted.org/lohitIn 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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_003_off0000e6ec.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0xE6EC 8448 bytes
SHA-256: f09f4c8ee3e1b5559f64083b74e6318140fa4749fbc287ac0927288e6672e2c4
font_00_sfnt_off0000d56d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD56D 5140 bytes
SHA-256: 01c1d51c6d3fe6b8ed19c8ad4ea95fa48199e5a1b6b7c4e234bc4b1f590acbf6
font_02_sfnt_off0000ff4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF4F 10848 bytes
SHA-256: efc154edc0feeeb63e8f319e389980f74de7f2db7991e465fcf785ef2062d115
font_03_sfnt_off00012497.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12497 16204 bytes
SHA-256: a95eff378c135b1ab40d10b3cd1da1bafbc07f86005f57898d079c90d712ddbd

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