Malicious PDF — malware analysis report

Static analysis result for SHA-256 4af8a351b7462ed4…

MALICIOUS

PDF

68.4 KB Created: 2021-06-25 04:34:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-29
MD5: 8e43b5131cc71a0f0f0279ce7a362a45 SHA-1: 0b37e9969f49719e3a0cc970f68174e07f06220d SHA-256: 4af8a351b7462ed43e5f5602ee753ebda8b682c12fd87da1eecfc84af7d12314
156 Risk Score

Malware Insights

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

The sample was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, directing users to multiple external URLs, some hosted on compromised CMS platforms. The PDF document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, and the presence of external URIs points towards a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9989

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://garglob.ru/uplcv?utm_term=quijote+dela+mancha+pdf PDF link annotation
    • http://valleypainclinic.org/userfiles/file/buzogozitifidiwusalagem.pdfIn PDF document text
    • http://zawayakw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e3eac32071---gobugenulogazejigugoguxuf.pdfIn PDF document text
    • http://vandientuchinhhang.com/upload/files/44805532481.pdfIn PDF document text
    • https://velvetskin.pl/wp-content/plugins/super-forms/uploads/php/files/536fb74aded82852f6edc7f2102fa036/jodozasopixinomuvotimevu.pdfIn PDF document text
    • https://grand-forge.ru/wp-content/plugins/super-forms/uploads/php/files/75bf14f6dc0f0eb39387c8e2f79858c2/44084041531.pdfIn PDF document text
    • http://www.xpresswedding.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608013777147e---39193855607.pdfIn PDF document text
    • https://www.gsccn.it/wp-content/plugins/formcraft/file-upload/server/content/files/160aef357a716b---xudamirojevitu.pdfIn PDF document text
    • https://apsco.ly/userfiles/files/nepawa.pdfIn PDF document text
    • http://www.petersmetalstitching.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/16075451d82e4c---butasulefobiwu.pdfIn PDF document text
    • https://infotechloyalty.com/bot/ckfinder/uf/files/foxakemawexerewejiduro.pdfIn PDF document text
    • https://www.zulilighting.com/wp-content/plugins/super-forms/uploads/php/files/ee7dfa1a8d4c994d9f6dea48aee898a7/mibokapoxomuzujiborufab.pdfIn PDF document text
    • http://www.drop-lok.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c030e55bf66---19216053278.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16074cf85a3421---66672342561.pdfIn PDF document text
    • http://asja-doll.ru/userfiles/file/83408115606.pdfIn PDF document text
    • https://www.dentaltaxpros.com/wp-content/plugins/super-forms/uploads/php/files/ba4a58ecf5573dd818d871ad8607b2cd/nodegarit.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ca8f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA8F 5256 bytes
SHA-256: 10f64e860266b38d769c686aee4224102991dad2913a09d2a98b5c0c9e095af8
font_01_sfnt_off0000dc5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC5A 14148 bytes
SHA-256: 8743b74fca2bf6301707367d8e1d1f07faea161e2fd6c6641db832ac858c9080

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