Malicious PDF — malware analysis report

Static analysis result for SHA-256 f7c538d5130a481e…

MALICIOUS

PDF

81.7 KB Created: 2021-02-25 09:16:54 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-16
MD5: dacb254e53c32858f726cb4dd6301b1c SHA-1: bde0ef1c01ae5edbfbb361dcd709391b1670ba7d SHA-256: f7c538d5130a481e656c380af2c314d7e5ee78213a64e6d207e682b857ba5a44
244 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of embedded links pointing to external PDF files hosted on various disposable domains, indicating a link farm or SEO manipulation tactic. Several heuristics confirm the malicious nature of these links, including flagging them as belonging to a malicious redirector and a disposable link farm. The ML classifier and ClamAV detection further support the malicious verdict.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://yafferge.ru/123?utm_term=games+like+nancy+drew+her+interactive In PDF document text
    • http://tijudozi.scienceontheweb.net/how_to_heat_my_coleman_hot_tub.pdfIn PDF document text
    • https://derigibi.weebly.com/uploads/1/3/4/4/134447264/6057813.pdfIn PDF document text
    • https://vakenufepuxino.weebly.com/uploads/1/3/4/5/134529081/xewemorirux_borun.pdfIn PDF document text
    • http://vitofemegawe.getenjoyment.net/what_does_chronological_text_mean.pdfIn PDF document text
    • https://cdn.sqhk.co/nuzinipaz/YthcJ4G/fetonok.pdfIn PDF document text
    • https://toxofeleziwogiz.weebly.com/uploads/1/3/1/4/131406173/ponewagenu.pdfIn PDF document text
    • https://kezexawu.weebly.com/uploads/1/3/0/8/130814062/678b6e4198af3d.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416927/normal_60317f85db51a.pdfIn PDF document text
    • http://gepexoliv.medianewsonline.com/do_all_wifi_thermostats_require_c_wire.pdfIn PDF document text
    • https://vusimipemukebev.weebly.com/uploads/1/3/0/8/130814393/9524019.pdfIn PDF document text
    • http://zimezobot.getenjoyment.net/roomba_780_replacement_parts.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_off00010179.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10179 5528 bytes
SHA-256: 2211cce641b7abf7f2dc5a372bd6c0f84f70634b84d4e9127fc8a5efee6cdade
font_01_sfnt_off0001143a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1143A 11208 bytes
SHA-256: ac78ad2c17f9bd7e0caf4984e5ff0339c5ff778d69515e477248ca35088f239a