Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c4357578a4aaa15…

MALICIOUS

PDF

90.0 KB Created: 2021-10-05 08:54:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: a7814acaabab67f627467d744c6b74b0 SHA-1: 395fe8bea9eb95822ac4af1675c82c8c5f6a96bd SHA-256: 4c4357578a4aaa159c559ebaf3a1d81d7be2eba55fd7e273367d06c00fd61726
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous external URIs and is structured as a link farm on disposable hosting, indicating a likely attempt to redirect users to malicious websites for phishing or malware distribution. The presence of external URIs and the link farm structure strongly suggest an attack pattern involving directing users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://queure.ru/uplcv?utm_term=are+you+smarter+than+a+5th+grader+multiple+choice+questions+and+answers PDF link annotation
    • http://businesslegalgroup.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/93361157376.pdfIn PDF document text
    • http://tobn56.com/UpFiles/file/butapifaxidumetenojubi.pdfIn PDF document text
    • http://www.wcd.com.tw/ezadmin/ckfinder/userfiles/files/14792463061.pdfIn PDF document text
    • http://solamsys.com/userData/board/file/18081335950.pdfIn PDF document text
    • https://10kshot.com/customerinterview/ckfinder/userfiles/files/vesekudigixejikakinit.pdfIn PDF document text
    • http://getwealthythisyear.com/ckfinder/userfiles/files/zasepitadezaga.pdfIn PDF document text
    • https://2winit.com/Files/files/4626268230.pdfIn PDF document text
    • https://www.ftha.org/admin/ckfinder/userfiles/files/84961525822.pdfIn PDF document text
    • https://yenhuy.vn/upload/files/pibixogekudasorufizu.pdfIn PDF document text
    • http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614369909f5cc---leruradesokufaxo.pdfIn PDF document text
    • https://tradingphrases.com/userfiles/files/jugamevumira.pdfIn PDF document text
    • http://saludocupacionalpso.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/161543d74bd2ae---30137724618.pdfIn PDF document text
    • https://doina.md/fckeditorfiles/file/kotawuzaku.pdfIn PDF document text
    • http://selfmadefilms.nl/userfiles/files/sekonefexulibolinitu.pdfIn PDF document text
    • https://leunamgroup.com/wp-content/plugins/super-forms/uploads/php/files/b7a14b3399f412652a45572291421d82/magexoruro.pdfIn PDF document text
    • https://lecormier-menuiserie.com/www/upload/files/jabugodijakulufavidev.pdfIn PDF document text
    • http://xn--3e0b556bhrbowi6undva.com/ckupload/files/25134528903.pdfIn PDF document text
    • http://christopherspubandgrille.com/userfiles/files/vugowelof.pdfIn PDF document text
    • https://freeunlock.com/uploads/file/pinaragiximiromuwedagenim.pdfIn PDF document text
    • http://studiotecnicoforace.eu/userfiles/files/sasavibuwoj.pdfIn PDF document text
    • http://backkwang.com/userData/board/file/47402079080.pdfIn PDF document text
    • https://mai-avto.ru/upload_files/file/vowesudowujekug.pdfIn PDF document text
    • http://gradn.ru/uploades/fckeditorfile/wojiremidizozesubizusog.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_off0000f44c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF44C 19748 bytes
SHA-256: 3bb8f20e5143ee5b8e13eedee93fbd03fc93a565b87d80743741d7655e93148b
font_01_sfnt_off00012732.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12732 11520 bytes
SHA-256: cac5472f0e98f3560bdbf750090945e5c8d3f687446a2520c784413f80cc3811
font_02_sfnt_off000141fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x141FA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1