Malicious PDF — malware analysis report

Static analysis result for SHA-256 51258fb7e96d4782…

MALICIOUS

PDF

77.5 KB Created: 2021-09-11 19:15:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 3b30cbb06394bf044d40228ee1ab5dc6 SHA-1: 9b73b207cbbe82cc41966ab4a95fef5128107aa3 SHA-256: 51258fb7e96d4782b9a6026d47340dacc4a88c3de7d0b397438bd0196d13f23a
126 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 PDF files on various domains, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a high number of distinct hosts, reinforcing the idea of a phishing or malware distribution campaign. No scripts were extracted, but the presence of external URIs and the overall structure point towards an attempt to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

Heuristics 5

  • 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.
  • 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://bauarch.bg/files/41065175321.pdf In PDF document text
    • http://controlsystemco.com/cache/fck_files/file/rixawowuloxev.pdfIn PDF document text
    • http://avrig35.ro/uploads/fck_editor/file/zejatisowebetagojubidi.pdfIn PDF document text
    • http://tochuchoinghi.org/files/78018947008.pdfIn PDF document text
    • http://sibzakon.ru/ckfinder/userfiles/files/48786193839.pdfIn PDF document text
    • https://netiko.ge/img/Data/file/xegedadalukipitujidif.pdfIn PDF document text
    • https://jodhpurtravels.com/nbloom/fckuploads/file/56836037840.pdfIn PDF document text
    • http://bkmarine.net/ckfinder/userfiles/files/1631139124.pdfIn PDF document text
    • http://aloisiquadri.it/userfiles/files/funototawobuvosofamaj.pdfIn PDF document text
    • http://adance0112.com/upfile/editor/file/83060658738.pdfIn PDF document text
    • https://cncunse.com/d/files/jodisewom.pdfIn PDF document text
    • http://eaas-journal.org/survey/userfiles/files/lapixekulelijuvaworakub.pdfIn PDF document text
    • http://jsqnchem.com/upload/files/46422227521.pdfIn PDF document text
    • https://lee-trading.tw/archive/upload/files/23698927352.pdfIn PDF document text
    • http://posicert.com/upload_fck/file/2021-9-7/20210907120038725563.pdfIn PDF document text
    • http://aokisuper.com/ckfinder/userfiles/files/gamaka.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139ca0fd5afd---doruwadebavamazazutuka.pdfIn PDF document text
    • http://xn----otbbfbbknchz.xn--p1ai/sadm_files/nivunijokomusuluzafepum.pdfIn PDF document text
    • https://www.avenueroadadvertising.com/wp-content/plugins/formcraft/file-upload/server/content/files/161336134c3eac---32645812769.pdfIn PDF document text
    • https://faktxeber.com/resimler/files/manabixiku.pdfIn PDF document text
    • http://pass38.com/images/contentimages/files/favifuzidasokozeba.pdfIn PDF document text
    • https://rsvforum.com/userfiles/file/levimifojusemonowo.pdfIn PDF document text
    • http://kutscher-customs.de/gfx/userfiles/files/98985524056.pdfIn PDF document text
    • https://producto.works/userfiles/file/552063777.pdfIn PDF document text
    • http://pttaccounting.com/userfiles/files/22572862765.pdfIn PDF document text
    • https://fundacjanadzieja.com/images/wyswig_images/file/91883108955.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=sw+kotor+android+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_off0000c9db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9DB 17692 bytes
SHA-256: 597e2134fdfc75e781de607fd03cff147c0e21a2f3befd0b28bac9e9a6c4f5ae
font_01_sfnt_off0000f75a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF75A 10292 bytes
SHA-256: fc8b03f711590965495f72cebcdf2bfa9206f76c6a451a453964276883916d9d
font_02_sfnt_off00010eb3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EB3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1