Malicious PDF — malware analysis report

Static analysis result for SHA-256 1c6b87eba8fd9369…

MALICIOUS

PDF

92.8 KB Created: 2021-03-02 14:23:48 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: d231ed54128cc7fa5b8c7ba891cfe74e SHA-1: 234665f6a3f6ed3ea09b7d43ae395c6046b32a3e SHA-256: 1c6b87eba8fd9369806099bd25dfccbef7f4c000e1502c446c16290999c68965
186 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many pointing to disposable hosting, suggesting a link farm designed to distribute malicious content or engage in phishing. The primary lure appears to be "Gmat verbal practice questions and answers - pdf", directing users to a suspicious URL. ClamAV and ML classifiers strongly indicate maliciousness, with the PDF being detected as a phishing trojan.

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://seumenha.ru/strik?utm_term=gmat+verbal+practice+questions+and+answers+-+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4462093/normal_601175b724f1f.pdfIn PDF document text
    • https://fomodaduvi.weebly.com/uploads/1/3/4/7/134700625/sinosezaga-nojenosaparut-xipojowul-dakakum.pdfIn PDF document text
    • https://xododasewa.weebly.com/uploads/1/3/4/6/134600374/xodudoke.pdfIn PDF document text
    • https://nivumumati.weebly.com/uploads/1/3/4/7/134703955/bijonamizesafil.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4446511/normal_60323a2857650.pdfIn PDF document text
    • http://metazoaapc.fun/carpenter_star_quiltumlmk.pdfIn PDF document text
    • https://cdn.sqhk.co/kimorotadopo/Xhcghhh/11606738632.pdfIn PDF document text
    • https://kigadipokifexi.weebly.com/uploads/1/3/0/8/130813079/2786051.pdfIn PDF document text
    • https://gejiraje.weebly.com/uploads/1/3/2/7/132740564/17ef420768c89b.pdfIn PDF document text
    • https://bituxusod.weebly.com/uploads/1/3/4/3/134347303/xulod_kijeju_nixudifavamozu_nefux.pdfIn PDF document text
    • https://kagopibuxewiki.weebly.com/uploads/1/3/1/3/131398156/b7fce.pdfIn PDF document text
    • https://vorupegesozuzow.weebly.com/uploads/1/3/1/4/131453293/241598c57.pdfIn PDF document text
    • https://nitomono.weebly.com/uploads/1/3/1/4/131454496/roregor-sogutegarexoz-panepa-setogen.pdfIn PDF document text
    • http://zolekumosex.iblogger.org/free_printable_ag_word_family_worksheets.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://bexadujozopu.epizy.com/best_gangster_games_for_android_2016.pdfIn PDF document text
    • http://sudebitije.rf.gd/1286670796.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_off00012d8a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D8A 5784 bytes
SHA-256: 6a492229b951e8ae1c16599e85d65a0867d17bd67afd3587ba81fe1a463f4ec2
font_01_sfnt_off00014135.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14135 10716 bytes
SHA-256: 5b993ae2bc597489b4448ad1b56d573d448e09a5b7a2d53ef8ad6b1dd550db84

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