Malicious PDF — malware analysis report

Static analysis result for SHA-256 70cbe4db3a566d9c…

MALICIOUS

PDF

64.4 KB Created: 2021-02-24 02:06:30 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: b0a0424cd052729c5d77fcab98443d82 SHA-1: 6098c94af140c0d0b62d40409d3480bf42654ce1 SHA-256: 70cbe4db3a566d9c9d20103e193f0400aad50c6a1664ec28f490e144ef66c00f
186 Risk Score

Malware Insights

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

The PDF file contains numerous external links, identified by the PDF_SEO_LINK_FARM and PDF_SEO_DISPOSABLE_LINK_FARM heuristics. The document body, though heavily obfuscated, suggests a lure related to 'Fractions in equations worksheet answers'. The primary malicious activity appears to be the creation of a link farm, directing users to various external PDF documents hosted on potentially disposable domains, as indicated by the high number of distinct hosts and the presence of disposable hosting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • 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://baarspo.ru/wix?keyword=fractions+in+equations+worksheet+answers PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4490138/normal_5fe43302a4d35.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4482216/normal_601260252512f.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4490274/normal_5fc953ffeb990.pdfIn PDF document text
    • https://bovuzujavus.weebly.com/uploads/1/3/5/3/135326818/657f05ded12f.pdfIn PDF document text
    • https://zafasasuk.weebly.com/uploads/1/3/4/7/134713251/98b6afa04b2cc.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4414848/normal_6019f370d8c33.pdfIn PDF document text
    • http://arfesopt.com/engineering_economy_7th_edition_answ747lx.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4406464/normal_6022436ee715d.pdfIn PDF document text
    • http://tesar-krd.ru/hyderabad_chatal_band_music_mp3_downloadp9pjg.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4365998/normal_6029d15230ce7.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4376098/normal_5fd8ee8c98a4e.pdfIn PDF document text
    • http://rbqjkwklnd.xyz/7050010568xj2gw.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4485157/normal_5ff693c304e03.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4390057/normal_5fee8ff10f9e9.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4453108/normal_601f22d62c170.pdfIn PDF document text
    • https://wavimukuwu.weebly.com/uploads/1/3/0/8/130874629/8567716.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_off0000bf40.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBF40 5092 bytes
SHA-256: c5d985a3ed1cadb06407794c2cf881e31848cfaf826cae28996cd20cdd815638
font_01_sfnt_off0000d0a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD0A4 10624 bytes
SHA-256: 3898b1c3e13ab2f31591aa4c949d9bbb9c9c6a1a318871ac1d3520f3f82a5929

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