Malicious PDF — malware analysis report

Static analysis result for SHA-256 c836926ec584121f…

MALICIOUS

PDF

70.8 KB Created: 2021-02-18 20:45:55 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 7d30605853c33524afbd95f27e15e060 SHA-1: ea1c1e729d4712eb1c330217aab8d842d6a8cec7 SHA-256: c836926ec584121f15d619ebca06912c27ad6c6eaf8e1d7620bb3e070045c6d8
244 Risk Score

Malware Insights

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

The sample was identified as malicious by ClamAV and an ML classifier, and it contains a large number of embedded links. Several heuristics indicate it is a link farm, with one critical finding pointing to a known malicious redirector. The document body, though heavily corrupted, contains text related to organizational culture, which is likely a lure to disguise the malicious intent of the embedded links.

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
  • 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://crophysi.ru/strik?utm_term=what+are+the+main+components+of+an+organizational+culture+and+why+are+they+important In PDF document text
    • https://zupalopozaguri.weebly.com/uploads/1/3/2/3/132302876/tabexutozuk.pdfIn PDF document text
    • http://joblanc.xyz/honorarium_payment_guidelines_south_africaq6kjk.pdfIn PDF document text
    • http://kernig.pro/counter_strike_1._6_cd_hackg6t1c.pdfIn PDF document text
    • https://risogaruwakev.weebly.com/uploads/1/3/4/6/134634919/5518772.pdfIn PDF document text
    • http://minuette.me/forming_and_solving_equations_worksheetmcpeu.pdfIn PDF document text
    • http://teenagetutor.online/nojejitepixem8ki3v.pdfIn PDF document text
    • https://fewanisip.weebly.com/uploads/1/3/2/7/132712603/f9c7a580c63e83.pdfIn PDF document text
    • https://navojinalano.weebly.com/uploads/1/3/4/7/134755450/f75aade1c44983d.pdfIn PDF document text
    • http://kewisanoxiv.66ghz.com/java_8_for_64_bit.pdfIn PDF document text
    • https://jadufebifov.weebly.com/uploads/1/3/4/6/134627690/fogidaz-gipuvufiwak-tirufaxaz.pdfIn PDF document text
    • http://autoupgrade.website/29175493459y5wod.pdfIn PDF document text
    • http://simkosa.website/968319963334f4iw.pdfIn PDF document text
    • http://fbcopyright-center.com/knowledge_matters_promotion_with_social_media_answers83dw8.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://zoletiwosi.rf.gd/53321863698.pdfIn PDF document text
    • http://mutodilevo.epizy.com/63451137145.pdfIn PDF document text
    • http://merekum.rf.gd/shinola_argonite_5021_manual.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_off0000d570.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD570 5828 bytes
SHA-256: 2fca4a443f80cea87e0e1f6c34b1c3f85577fb90bdbfa17eec4c019f58233d56
font_01_sfnt_off0000e943.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE943 10512 bytes
SHA-256: c71f6e4a54d05284eeca7d88ce1aa1a8705149959a01842c42bf4ef7d1d54014

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