Malicious PDF — malware analysis report

Static analysis result for SHA-256 550977e95ee3dd1d…

MALICIOUS

PDF

77.9 KB Created: 2021-03-03 21:46:50 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-17
MD5: 14b370e437b367256ca6e078f782be13 SHA-1: cd9dee9e34c56612f7ec11520a1b7b1d58be97ac SHA-256: 550977e95ee3dd1d6301bff85263e0af2dafada5fdfab8338bd6c9ef1a247efa
156 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF contains a large number of external links, identified by the PDF_SEO_LINK_FARM heuristic, pointing to various PDF files. One of the primary external links, https://jottigo.ru/strik?utm_term=experiments+in+physical+chemistry+shoemaker, is flagged as suspicious. The ML classifier and ClamAV detection strongly indicate maliciousness, with ClamAV identifying it as Pdf.Phishing.Trojan. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create SEO-optimized content farms that can host malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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.
  • 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://jottigo.ru/strik?utm_term=experiments+in+physical+chemistry+shoemaker PDF link annotation
    • https://cdn.sqhk.co/nowagenika/Dhghcgi/diguzivawuj.pdfIn PDF document text
    • https://cdn.sqhk.co/xulawajikigi/jhOLghD/xonalez.pdfIn PDF document text
    • https://cdn.sqhk.co/toxinize/hyhg1ij/mobevodapetepi.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4477183/normal_6017253163f9c.pdfIn PDF document text
    • https://kimilofu.weebly.com/uploads/1/3/0/8/130873947/nosaxulutinelog_vejuxateduxuba_sekurovuzot_luragiw.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4412391/normal_6001711bc80c2.pdfIn PDF document text
    • https://lowarimubabop.weebly.com/uploads/1/3/4/7/134712264/minidoruji_jidoxazezise.pdfIn PDF document text
    • https://cdn.sqhk.co/jajotulix/ehgl8cO/vibab.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/wulagisi/presion_de_cavidades_cardiacas.pdfIn PDF document text
    • https://s3.amazonaws.com/rezugekolaba/zefidodoterujug.pdfIn PDF document text
    • https://s3.amazonaws.com/kagedatabujo/52090309364.pdfIn PDF document text
    • https://s3.amazonaws.com/dosalapasenow/botanica_oculta_paracelso_gratis.pdfIn PDF document text
    • https://s3.amazonaws.com/mizeteb/xubuseruxazuniz.pdfIn PDF document text
    • https://s3.amazonaws.com/dozore/6318913553.pdfIn PDF document text
    • https://s3.amazonaws.com/wovisak/conclusion_of_final_report_industrial_training.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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dee5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEE5 5364 bytes
SHA-256: 95052ff31426d526e0120f2d50731d1b3a07a46e295065178ccf22cd92318349
font_01_sfnt_off0000f107.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF107 10500 bytes
SHA-256: 48aa5b0ed27fe6fe0c8e035495bfc6e4f79b47565b23ce6bd2cd0cad4ccc3761
font_02_sfnt_off00011512.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11512 16192 bytes
SHA-256: 4092b845889decd8837f45f2eddc52b163c40db4fcd3fa680519e1f98a2270b5

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