Malicious PDF — malware analysis report

Static analysis result for SHA-256 b87c886224df5f77…

MALICIOUS

PDF

75.7 KB Created: 2021-09-26 02:18:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 5538575c07e1a28bbc0efe86c2b6f297 SHA-1: 2ad1e985c9b23f0dc0028d77099bcd38624fed4a SHA-256: b87c886224df5f77a8da0879c7f94e4a4b6e4547151e1b9b9ab884eda89ff777
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. The document contains numerous embedded URLs, many of which are part of a link farm hosted on disposable domains, suggesting an attempt to obscure the ultimate destination. One URL specifically mentions 'docs reader apk', indicating a lure for users to download potentially malicious software.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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://www.uniqueartzz.com/wp-content/plugins/super-forms/uploads/php/files/ng418clgpra8aqlhuvf8gv2mt7/31737536218.pdf In PDF document text
    • http://cp-tournament.org/ckfinder/userfiles/files/18450506953.pdfIn PDF document text
    • http://ecohouse-lab.de/userfiles/file/37259310587.pdfIn PDF document text
    • http://interno-kazan.ru/upload/files/82590565877.pdfIn PDF document text
    • http://inwallendorf.de/userfiles/file/55067941757.pdfIn PDF document text
    • https://centrumschoolka.pl/photos/file/sutunofegufidepub.pdfIn PDF document text
    • http://leruichem.com/upload/files/pivesodefevoret.pdfIn PDF document text
    • http://mavelikaradiocese.org/rapha/ckfinder/userfiles/files/93489950317.pdfIn PDF document text
    • http://www.chiringuitomediterraneo.com/ckfinder/userfiles/files/99173372314.pdfIn PDF document text
    • https://dianthusindustrial.com/resimler/files/23983196185.pdfIn PDF document text
    • http://szpitalstrzelin.pl/userfiles/files/bunuxobikosolazemela.pdfIn PDF document text
    • https://dalycity.com/wysiwygfiles/file/dixuwavitinowinukan.pdfIn PDF document text
    • http://www.urbanwaterways.info/files/30523839014.pdfIn PDF document text
    • https://rosettes.it/userfiles/file/65894943444.pdfIn PDF document text
    • https://woodfur.in/userfiles/file/19064356054.pdfIn PDF document text
    • http://receptlap.hu/files/96551664825.pdfIn PDF document text
    • http://dae-young.kr/upload/fckeditor/file/zedetevimi.pdfIn PDF document text
    • http://architettoannalisatinelli.it/userfiles/files/74205458541.pdfIn PDF document text
    • http://sunnyten.net/userData/board/file/62601517268.pdfIn PDF document text
    • http://szguilong.com/userfiles/files/lafofanenuboditanole.pdfIn PDF document text
    • https://muguet.fr/sites/default/files/file/darejex.pdfIn PDF document text
    • http://kapalishakti.com/ckfinder/userfiles/files/5623805477.pdfIn PDF document text
    • https://aksukartela.com/images_upload/files/bewezeponedefa.pdfIn PDF document text
    • http://js-space.de/userfiles/file/21836221202.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=docs+reader+apkPDF link annotation
    • 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_off0000c01e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC01E 10260 bytes
SHA-256: 28b59e2792b57768afae7f594ca15a830865354bc7dadcd4f7f661af2856b483
font_01_sfnt_off0000d745.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD745 19220 bytes
SHA-256: 0a89718925f349f7f6b4429bf29ac5cc448ab550a9d19c6ea007a989d86e2f7e
font_02_sfnt_off0001099e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1099E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1