Malicious PDF — malware analysis report

Static analysis result for SHA-256 42a8b257bf2ac9d9…

MALICIOUS

PDF

81.4 KB Created: 2021-09-16 12:09:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 2927178e36179679a9205ddc5d93f1f0 SHA-1: 1cfe377442a249850128a9691f005ba0d495e370 SHA-256: 42a8b257bf2ac9d93bfe2ae9df3b13084cd8106c9f2f2d157350a152cfebae71
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm on disposable hosting. Numerous embedded URLs point to external sites, suggesting a phishing or malware distribution scheme. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_URI heuristics strongly supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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://coretry.ru/uplcv?utm_term=how+to+receive+group+messages+on+android PDF link annotation
    • http://signauction.net/userfiles/file/kovilesedatesug.pdfIn PDF document text
    • http://yameitecl.com/ckfinder/userfiles/files/20210916_025732.pdfIn PDF document text
    • https://tailormade-sales-marketing.com/userfiles/file/73497118180.pdfIn PDF document text
    • http://4chan.ro/UserFiles/file/8707790067.pdfIn PDF document text
    • https://rotterdampools.com/contents/files/jixiduron.pdfIn PDF document text
    • https://hanurichurch.org/ckfinder/userfiles/files/52946964907.pdfIn PDF document text
    • http://recit-de-vie.fr/userfiles/file/rujoxabike.pdfIn PDF document text
    • http://gddfboiler.com/uploads/files/kirufika.pdfIn PDF document text
    • https://malmospelmanslag.se/userfiles/file/pesabe.pdfIn PDF document text
    • https://mongolia-volkslift.com/uploads/files/9727962931.pdfIn PDF document text
    • https://taucaotoccatba.vn/images/news/files/99469747879.pdfIn PDF document text
    • https://concurs-euclid.ro/upload/fck/xiretejenobuvaruditek.pdfIn PDF document text
    • http://korea-labels.com/ckfinder/userfiles/files/rawojavepeni.pdfIn PDF document text
    • https://www.popcaffe.it/wp-content/plugins/super-forms/uploads/php/files/ae05939e1561abb0ab32176631be5b04/lewisoveparu.pdfIn PDF document text
    • https://hsse.cl/files/90804723685.pdfIn PDF document text
    • https://upaspor.com/resimler/files/topom.pdfIn PDF document text
    • http://designbeginnings.com/upload/file/duzarezuguwuda.pdfIn PDF document text
    • http://wolfroccatiassociati.it/userfiles/files/digixafigexupuge.pdfIn PDF document text
    • https://dobski.pl/userfiles/file/22735106937.pdfIn PDF document text
    • https://groupunsur3.com/contents/files/dexulizugo.pdfIn PDF document text
    • http://bxbrdh.marketsearching.com/upload/files/gegibidifegisudebu.pdfIn PDF document text
    • https://rajatotogroup2.com/contents/files/dukosibegasubalibul.pdfIn PDF document text
    • http://www.farmaciapenil.es/userfiles/files/77798409372.pdfIn PDF document text
    • http://karinameal.com/imgdish/files/1548902874.pdfIn PDF document text
    • http://swapnakoodu.com/fck_uploads/file/voborapufigidok.pdfIn PDF document text
    • http://japanbizkorea.com/userData/ebizro_board/file/25609925.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_off0000d77b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD77B 11052 bytes
SHA-256: e6e6731c7095daa426661e39f725a7dd780e38ee4b6e6033ade6dd3792dc2d29
font_01_sfnt_off0000f112.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF112 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010924.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10924 17652 bytes
SHA-256: 19831237069efd6c7840d07e8db987845327c8341247f5ea5f51c1f21af71de4