Malicious PDF — malware analysis report

Static analysis result for SHA-256 c6d7a0ed76b4bc73…

MALICIOUS

PDF

72.8 KB Created: 2021-09-17 15:06:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 9fa96cbb1dcefc5713cd2cac0601e8ed SHA-1: 0ecedfe25b313845e9500dc7064765dcf785007a SHA-256: c6d7a0ed76b4bc73d84c0a49a50e4551d919bc8aef2cadfa1f9b645f81cdc9d3
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains an embedded JavaScript stream and numerous external URIs pointing to disposable hosting, characteristic of phishing or malware distribution schemes. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports that the document is part of a link farm designed to host many links on potentially untrusted domains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://allytemp.ru/uplcv?utm_term=machine+learning+exam+questions+and+answers+pdf PDF link annotation
    • https://larioenergy.net/uploads/file/35357584746.pdfIn PDF document text
    • https://ngoctraithaibinhduong.com/uploads/news_file/11352405192.pdfIn PDF document text
    • https://eastmangroup.org/ckfinder/userfiles/files/41121904769.pdfIn PDF document text
    • http://esrafisek.com/images_upload/files/55918339565.pdfIn PDF document text
    • http://chistogood.ru/admin/ckfinder/userfiles/files/4190360566.pdfIn PDF document text
    • http://zae.me/datafiles/file/gugovowarumazamo.pdfIn PDF document text
    • https://www.alitec.es/js/ckfinder/userfiles/files/36086270294.pdfIn PDF document text
    • http://photou.cc/ckfinder/userfiles/files/bujufuxasugefuwepin.pdfIn PDF document text
    • http://trips-in.com/ckupload/files/jenuwovivebu.pdfIn PDF document text
    • http://zapatosperezcabrera.com/ckfinder/userfiles/files/diramim.pdfIn PDF document text
    • http://pro-group.ru/userfiles/file/sovijalutudalojofu.pdfIn PDF document text
    • https://gangnampools.com/contents/files/vamelekibexi.pdfIn PDF document text
    • https://chinatupai.com/web/js/ckfinder/userfiles/files/zuluwapigitevofusavulan.pdfIn PDF document text
    • https://maisonforville.be/documents/file/bapabobolinovuwakisobon.pdfIn PDF document text
    • https://liho.cz/UserFiles/File/temusogonuxuduloxav.pdfIn PDF document text
    • http://domosplast.hu/files/file/bovibifanaruvew.pdfIn PDF document text
    • http://rucodelniza.ru/userfiles/file/67482968061.pdfIn PDF document text
    • https://beta.nhatthiengroup.com/files/uploaded/files/vipowuzikom.pdfIn PDF document text
    • http://www.ecostroyservis.ru/File/408956928.pdfIn PDF document text
    • https://beytarimcilik.com/admin/editor_resim/file/40164748907.pdfIn PDF document text
    • http://ttmplus.com/userfiles/files/wigidumewujadag.pdfIn PDF document text
    • http://sinojjacob.com/userfiles/file/19343560462.pdfIn PDF document text
    • https://newtop-eg.com/userfiles/file/badunaxo.pdfIn PDF document text
    • https://zlato-eu.cz/upload/files/bubivasenovuxiv.pdfIn PDF document text
    • http://schokozentrale.de/idata/vojegomofekijosagal.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://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_off0000b9ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB9EA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d201.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD201 11492 bytes
SHA-256: 25ff21f6b4b1fc46cc5ac5312178cab923e8f253f5cee552b6cea8a6026fb1b9
font_02_sfnt_off0000ec91.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC91 15796 bytes
SHA-256: fe848f42cfbaa31408e46979b47724393d00803dc348be46174a96d926b1e809