Malicious PDF — malware analysis report

Static analysis result for SHA-256 81fe738e7eddfc51…

MALICIOUS

PDF

80.3 KB Created: 2021-06-17 16:46:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-05
MD5: c98340a66aa3e63656389d1947d3b184 SHA-1: 2454047ae2ba2d032e5681af4196b9fe6d879c08 SHA-256: 81fe738e7eddfc51ed7e9bc84061678e4d02a698479c6aee4dc370a9fa0dc35d
156 Risk Score

Malware Insights

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

The PDF file contains a link farm designed to redirect users to potentially malicious content, masquerading as a 'free house flipper' offer. Several heuristics indicate the use of compromised WordPress sites for hosting these links, and the ML classifier strongly suggests malicious intent. While no scripts were explicitly extracted, the presence of numerous embedded URLs and the overall structure point towards a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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=free+house+flipper PDF link annotation
    • https://gz-topstar.com/wp-content/plugins/super-forms/uploads/php/files/64ebf7e9f7482f6967091cb43d2bce60/30712592093.pdfIn PDF document text
    • https://baileyelectrical.services/wp-content/plugins/super-forms/uploads/php/files/t39g87ap1i7qpeusb01osa2l77/92454698505.pdfIn PDF document text
    • https://growmytruck.com/wp-content/plugins/super-forms/uploads/php/files/14c692b49c06539e41ffaa04c57662b4/72534507060.pdfIn PDF document text
    • http://dogoxuavanay.vn/uploads/files/mofojux.pdfIn PDF document text
    • http://zaragozalawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/liler.pdfIn PDF document text
    • http://www.fotografoeventimilano.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e157cb7a12---89778020322.pdfIn PDF document text
    • https://www.criteriainvest.com.br/wp-content/plugins/super-forms/uploads/php/files/smdi1qkq2ahanuujuisec2e2c1/75390573369.pdfIn PDF document text
    • http://digemnd.com/UserFiles/file/kawudazedituwiwusep.pdfIn PDF document text
    • http://www.anjhimayath.com/upload/file/93329442678.pdfIn PDF document text
    • https://charterfori.ir/basefile/charterforiir/files/63765178779.pdfIn PDF document text
    • https://www.davidcosz.de/wp-content/plugins/super-forms/uploads/php/files/bif1re9j65hqp215csalps90td/94118249393.pdfIn PDF document text
    • https://dock-levellers.com/upload/files/18628564964.pdfIn PDF document text
    • http://quickfix-poland.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b87ee730790---42109532790.pdfIn PDF document text
    • https://artlabjo.com/userfiles/file/23975811578.pdfIn PDF document text
    • https://gauravkankariya.com/wp-content/plugins/super-forms/uploads/php/files/smorf4bn1khllh6gpahcuhl7t6/90936316895.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_off0000fd4e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD4E 4736 bytes
SHA-256: f1f857687987935203614874f0da64cdcfde513c5e6f98d3ed1a3ebc4bc33e99
font_01_sfnt_off00010d65.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D65 11076 bytes
SHA-256: 79cbb6ae3e7e46717373a6abbf16025c081399057ceec960640607ef3118c2d2

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