Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4b4fb5aa48552cb…

MALICIOUS

PDF

70.7 KB Created: 2021-09-21 12:06:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: cce6e6e7310cda689e372216b39183cb SHA-1: 2d43e10004bc0738040e58174db285e62633f018 SHA-256: c4b4fb5aa48552cbab187f2d6fed856ef1b22ee3ada65550c479f3b40864f01f
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, many of which point to suspicious domains and are likely used for phishing or to host further malicious content. The PDF structure is malformed, suggesting an attempt to exploit vulnerabilities or obfuscate its true nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://ijdssymposium.eu/upload/35408788690.pdf In PDF document text
    • https://bu8m3tas68s-b1.com/contents/files/temitekenoto.pdfIn PDF document text
    • http://zuche0551.com/upload/file/75858510471.pdfIn PDF document text
    • https://deycaterers.com/ckfinder/userfiles/files/wireroko.pdfIn PDF document text
    • http://pasted-radio.de/web/files/34855907763.pdfIn PDF document text
    • http://cukierniabrzezinski.pl/www/artizam/fck/file/33089305451.pdfIn PDF document text
    • https://etravelbox.com/scgtest/team-explore/uploads/files/boguvu.pdfIn PDF document text
    • https://fundacjanadzieja.com/images/wyswig_images/file/61778161564.pdfIn PDF document text
    • http://girc.ncue.edu.tw/ckfinder/ckfiles/files/famuvedomudil.pdfIn PDF document text
    • http://xboxheerlen.nl/userfiles/file/bubusokoxevamodux.pdfIn PDF document text
    • http://saxonrt.hu/img/userfiles/files/fowupegadilevajenonawute.pdfIn PDF document text
    • http://www.nanodrywash.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d119f12687---12578488658.pdfIn PDF document text
    • http://currycornersugarland.com/admin/images/file/sirerumu.pdfIn PDF document text
    • http://huabulaw.com/uploadpic/2021-9/file/2021090822490173499.pdfIn PDF document text
    • https://skyzoan.com/cake/beta/userfiles/file/73725255251.pdfIn PDF document text
    • http://chieucoingason.vn/files/zavafuregivasokebarot.pdfIn PDF document text
    • http://wakingbeauty.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b3d50ac8f4---35802775050.pdfIn PDF document text
    • http://dentish.ru/ckfinder/userfiles/files/pukekajetisibes.pdfIn PDF document text
    • https://shevtsov-art.com/uploads/files/42050196662.pdfIn PDF document text
    • http://mxag.com/upload/browse/file/fepumovawomojoturak.pdfIn PDF document text
    • https://prosaison.fr/userfiles/files/jubisos.pdfIn PDF document text
    • http://quesnelfoundation.ca/userfiles/file/xokuvidajurekemajakolova.pdfIn PDF document text
    • http://donateagift.eu/userfiles/file/gugapudosonumafoderij.pdfIn PDF document text
    • http://chokmanee.com/userfiles/file/37077638651.pdfIn PDF document text
    • http://omeofest.eu/userfiles/files/baxefatupigiposij.pdfIn PDF document text
    • https://karolinanowak.com/userfiles/file/lareniwedozaxilineri.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=draw+graph+of+quadratic+equationPDF 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_off0000b51b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB51B 14760 bytes
SHA-256: 9e8c7e84e7b3c4f6de7162fc3afef0c222d8bdb49c427293e017ace4ca2e6b96
font_01_sfnt_off0000d9e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9E5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f1fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1FC 11016 bytes
SHA-256: ca0a662536c83a48ded9aa9c0b023bd9dbd199d41aae315c8b32be8be790dd11