Malicious PDF — malware analysis report

Static analysis result for SHA-256 bf21619438ff89a8…

MALICIOUS

PDF

71.9 KB Created: 2021-10-01 18:02:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 866705f006bd306cd817ca3019611091 SHA-1: be9a3e91d430a4d2fb8306b880c63c09d3908908 SHA-256: bf21619438ff89a8e8508515feac0eb934a987cc91262a27c2338c5a0798ba32
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics, including a high-confidence ML classifier and ClamAV, indicating malicious content. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic suggests the document is designed as a link farm, pointing to numerous distinct hosts, with one prominent URL being https://coretry.ru/uplcv?utm_term=adb+local+adb+shell+apk. This pattern is consistent with phishing or malware distribution campaigns.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9909

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 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=adb+local+adb+shell+apk PDF link annotation
    • http://thamdinhgiadaiquang.com/img/files/18340457639.pdfIn PDF document text
    • https://uslugiinzynierskie.eu/eurostyl/photos/file/83574780961.pdfIn PDF document text
    • http://xn--90ad5ackt1d.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/49e2d0b46c2c32a62ff07671460308ac/meravelalaxozabetirujoti.pdfIn PDF document text
    • https://manhremhoangvan.vn/wp-content/uploads/files/bivosafa.pdfIn PDF document text
    • https://keluargamimpi.com/contents/files/68752032558.pdfIn PDF document text
    • http://macautemple.com/userfiles/file/wujivogemexa.pdfIn PDF document text
    • https://piataafacerilor.ro/app/webroot/files/userfiles/files/jizaxivur.pdfIn PDF document text
    • http://jinwoosmc.com/userfiles/file/75447697910.pdfIn PDF document text
    • https://clinicaabrahaoosta.com.br/ckfinder/userfiles/files/putibavixawagifova.pdfIn PDF document text
    • http://charugarware.com/DEVELOPMENT/charu_garware/uploaded/userfiles/file/62141538900.pdfIn PDF document text
    • http://ndt-tl.ru/upload/file/bomazugemikiv.pdfIn PDF document text
    • http://naturalfurnish.com/userfiles/file/binawikupaxem.pdfIn PDF document text
    • http://greenegiving.aboutgiving.net/sites/default/files/editor/file/56219350852.pdfIn PDF document text
    • https://weboonline.com/ckfinder/userfiles/files/remeginolaroxibifurizel.pdfIn PDF document text
    • https://snqrsl.quebec/upload/editor/file/78304281835.pdfIn PDF document text
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/38432521376e3dec4c59f6d9427bde85/jexov.pdfIn PDF document text
    • http://el-master.ru/userfiles/file/80804944126.pdfIn PDF document text
    • http://studiochiodo.eu/userfiles/files/31391077457.pdfIn PDF document text
    • http://purofirstli.net/userfiles/file/fosixibofipolofesezowig.pdfIn PDF document text
    • http://scouttautomotive.com/editor_uploads/system/files/bususagedosefemenaves.pdfIn PDF document text
    • http://hitelesen.com/userfiles/file/jisigosukupulodixaleso.pdfIn PDF document text
    • http://mondoacquapiscine.com/userfiles/files/totetuzilipubifuwav.pdfIn PDF document text
    • http://uniontsg96.ru/admin/ckfinder/userfiles/files/jorunaxorepamopajegig.pdfIn PDF document text
    • http://coimbra.hu/uploads/ckfinder/userfiles/files/pamojimobadujij.pdfIn PDF document text
    • https://knurussian.kr/DATA/upload/files/202109050249148988.pdfIn PDF document text
    • http://househouse.it/userfiles/files/sazepapu.pdfIn PDF document text
    • https://dukeofmarshall.com/ckfinder/userfiles/files/vosavoxanukanabefap.pdfIn PDF document text
    • http://leinerpakgelatine.com/survey/userfiles/files/pagepedafofujusigifisa.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_off0000b652.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB652 16472 bytes
SHA-256: 8e5e0ffa2913df8a69997d4ae63768982fc630a9a213be5c214fa82c7bd346bf
font_01_sfnt_off0000e065.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE065 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f87c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF87C 10432 bytes
SHA-256: 2deef207690d048bcaefb7c76bde579c8a3dbd2c23245c2ccbcb056c151a7fde