Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d4a3b0c198e2cd8…

MALICIOUS

PDF

71.7 KB Created: 2021-02-05 12:24:38 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-07
MD5: f556592d7a644e22f53ec71385886685 SHA-1: e15ed5dcbdc57dc6221306f7778b543c3cfd1471 SHA-256: 8d4a3b0c198e2cd851d48a232eef4aac4793eede7c159c25f4908e3f762d053e
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of external links, many pointing to disposable domains, which is characteristic of a link farm. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or malware distribution. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf, but the primary malicious activity appears to be the distribution of links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://jacksth.ru/aws?utm_term=analytical+research+paper+template PDF link annotation
    • http://edaruzal.xyz/66636303602qvobc.pdfIn PDF document text
    • http://siteznakomstv69.space/18775291141t2agq.pdfIn PDF document text
    • https://cdn.sqhk.co/kapimetavis/zhfDnjh/steam_table_temperature_controls.pdfIn PDF document text
    • https://kiwaluraxipexe.weebly.com/uploads/1/3/5/3/135326690/f9cc7790c01b7.pdfIn PDF document text
    • https://cdn.sqhk.co/rapawaferew/rahh8W0/paputo.pdfIn PDF document text
    • https://cdn.sqhk.co/wifepodilojo/UMigqhh/zububusigexalanifen.pdfIn PDF document text
    • http://dunizajo.66ghz.com/shakira_try_everything.pdfIn PDF document text
    • http://bbcua.site/rusa_en_ok_kullanlan_1000_kelime4v48j.pdfIn PDF document text
    • http://burrrhey.tech/sutifebenoluzelilumukinuf9c0b6.pdfIn PDF document text
    • https://gimiduti.weebly.com/uploads/1/3/4/7/134711596/4331622.pdfIn PDF document text
    • https://cdn.sqhk.co/rorefevobo/hcgeKqw/61674761048.pdfIn PDF document text
    • https://cdn.sqhk.co/madagijoj/ligm1gf/70378568124.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://jogirizuxaxoban.epizy.com/canon_pixma_ip1800_user_manual.pdfIn PDF document text
    • http://pazugovaru.rf.gd/63453272961.pdfIn PDF document text
    • http://wosolebaxuwutux.rf.gd/pesunitorivamejuf.pdfIn PDF document text
    • http://tininababa.rf.gd/hungry_jacks_app_apk.pdfIn PDF document text
    • http://lusiromipu.epizy.com/listening_worksheet_for_grade_2.pdfIn 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_off0000dc56.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC56 5264 bytes
SHA-256: 04b054e7f2f713d0415717df4ecbca4786055a20867e87ea507a43000fcc1940
font_01_sfnt_off0000ee1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE1A 10312 bytes
SHA-256: a82b1b1a6762f2ce111b0aca7063dcaf1c918647e659dc3f0f9fda0d6d103782

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