Malicious PDF — malware analysis report

Static analysis result for SHA-256 a9c86650317016b9…

MALICIOUS

PDF

71.0 KB Created: 2021-09-27 23:47:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 36415d6f644b5a723cf49e98d3a6cfd3 SHA-1: bf453bad4298b5fc5ab2b07aace955a431cbc9e0 SHA-256: a9c86650317016b95ae961e690882901b38393f5b3f8fddbc593c14be05dacc8
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was identified as malicious by ML classifiers and ClamAV, with high-confidence heuristics indicating a malformed exploit stream and a link farm on disposable hosting. The embedded URLs, despite some being marked benign, contribute to the overall pattern of directing users to potentially harmful sites. No scripts were extracted, but the PDF structure and heuristics suggest an attempt to exploit vulnerabilities or redirect users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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 http://www.smwiarus.pl/ckfinder/userfiles/files/79904333215.pdf In PDF document text
    • https://nicemexico.net/wp-content/plugins/formcraft/file-upload/server/content/files/16138d3ee3125b---disidur.pdfIn PDF document text
    • http://a-aqua.fr/ressource/site-image/files/rogoxifodilogawaben.pdfIn PDF document text
    • https://ardiinerkh.mn/uploads/userfiles/files/11072007425.pdfIn PDF document text
    • http://ranch.pl/files/file/titojepe.pdfIn PDF document text
    • https://deewo.de/wp-content/plugins/formcraft/file-upload/server/content/files/1614b28445e2cd---depokim.pdfIn PDF document text
    • http://cy2hand.com/userfiles/95845060898.pdfIn PDF document text
    • http://tupnate.com/ckfinder/userfiles/files/lasogemezosafozuxaw.pdfIn PDF document text
    • http://grupopiscis.com/upload/files/2323637848.pdfIn PDF document text
    • http://geotersrl.it/file/88206734717.pdfIn PDF document text
    • https://fultoys.com/userfiles/41741105693.pdfIn PDF document text
    • http://shopabrang.com/images/files/6879582374.pdfIn PDF document text
    • http://zatexpress.com/upload/userfiles/files/19311518645.pdfIn PDF document text
    • https://casasholidays.com/scgtest/team-explore/uploads/files/10815305410.pdfIn PDF document text
    • https://muachungbaohiem.com/uploads/userfiles/file/bikelosulodiwolarizez.pdfIn PDF document text
    • https://jagominum.com/contents/files/18183279746.pdfIn PDF document text
    • http://dok-vo.ru/userfiles/file/23702081744.pdfIn PDF document text
    • https://mumegram.com/userfiles/file/41016798309.pdfIn PDF document text
    • https://pioneerlift.com/upfiles/editor/files/duvumodatu.pdfIn PDF document text
    • http://prunay-en-yvelines.fr/ckfinder/userfiles/files/gisagipowibazodarilibixe.pdfIn PDF document text
    • http://audyt.rowerowaszkola.pl/imgturysta/files/bugetegejokigona.pdfIn PDF document text
    • http://thietbikhachsanvinhhung1.com/upload/files/mimovekanopekowigusedex.pdfIn PDF document text
    • http://evolution-dev.com/file_media/file_image/file/16511044015.pdfIn PDF document text
    • http://neapol-m.ru/usr/file/68392845066.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=game+balap+motor+online+androidPDF 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_off0000b27a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB27A 10564 bytes
SHA-256: 2cdb112fa3f2b75fa103277ddc65f56cdfdb36935c339e06e114fdd8eea9a2d5
font_01_sfnt_off0000ca3d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA3D 17176 bytes
SHA-256: 10b060c0180cfd48358b439025e197a58e20740832ef92a937ae5a1f7a2131b4
font_02_sfnt_off0000f614.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF614 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1