Malicious PDF — malware analysis report

Static analysis result for SHA-256 a557c6dbd70546e9…

MALICIOUS

PDF

80.7 KB Created: 2021-09-16 11:46:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: ccc4b38650fcd26fa3289f3eb79ed749 SHA-1: e87123f7e3e14bdbdc5a545b0bf40c9125a7b588 SHA-256: a557c6dbd70546e931e8c03ab4584903705d1950312a3ab6ab658ada2a166f68
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links to external PDF files, forming a link farm, and one of these links is presented as a search result for 'subway surfers cheats'. While no scripts were explicitly extracted, the PDF structure and the presence of external links suggest an attempt to redirect the user to malicious content, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://mraos.com/web/userfiles/file/pefij.pdf In PDF document text
    • http://ahjygjg.com/upload_fck/file/2021-9-11/20210911143442506031.pdfIn PDF document text
    • https://metnar.pl/web/uploads/files/59310614523.pdfIn PDF document text
    • http://udelimpa.es/ckfinder/userfiles/files/zafafibo.pdfIn PDF document text
    • http://tuanayapim.com/rsm/files/wemijetipinuvu.pdfIn PDF document text
    • http://modern-pro.ru/files/file/pimome.pdfIn PDF document text
    • http://cleversystems.ru/userfiles/file/38300811376.pdfIn PDF document text
    • https://fruitssupplier.com/app/webroot/img/files/15336684060.pdfIn PDF document text
    • https://marupyara.com/fotos/userfiles/file/lakujefogasakolex.pdfIn PDF document text
    • https://burragebrothers.com/demo/jolie/beta/userfiles/files/19019703452.pdfIn PDF document text
    • https://tourgardan.com/basefile/tourgardancom/files/80025230088.pdfIn PDF document text
    • http://hotelgiottotorino.com/userfiles/files/98246687399.pdfIn PDF document text
    • https://alwaysthesame.pt/site/upload/file/40281292804.pdfIn PDF document text
    • https://quatcongnghieput.com/uploads/files/189768898.pdfIn PDF document text
    • http://westernstudioservice.com/admin/userfiles/file/kaluraxegi.pdfIn PDF document text
    • http://annamsaigonlaw.com/upload/files/2107959872.pdfIn PDF document text
    • https://bloc-immo.com/images/83479806972.pdfIn PDF document text
    • http://bilagroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fe8c02ead9---vokozuxopawakedamu.pdfIn PDF document text
    • http://worldofpacifiers.com/editor_uploads/system/files/dapulatuxo.pdfIn PDF document text
    • https://cryptobasics.biz/uploads/files/32834042917.pdfIn PDF document text
    • https://sarna-zapiekanki.pl/ckfinder/userfiles/files/sitilewemebokulapo.pdfIn PDF document text
    • http://koreadramatour.com/FileData/ckfinder/files/20210908_936CD30B141BE7FB.pdfIn PDF document text
    • http://hillsclinic.com/fckeditor/editor/filemanager/connectors/php/userfiles/file/32285586117.pdfIn PDF document text
    • http://choragwica.pl/userfiles/file/48579927365.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=subway+surfers+cheats+unlimited+coins+and+keys+for+iphonePDF 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_off0000cf86.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF86 19156 bytes
SHA-256: 25ecaec1c655b095a14aa0b7f68a5fa31947c8ce1c6629dbc418aeb3002bdc49
font_01_sfnt_off0001020e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1020E 11492 bytes
SHA-256: b581f2d52da3871e5110b51a7ce3b78b165937d0ca89a7b92e734c3237dc1871
font_02_sfnt_off00011ce5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11CE5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1