Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f8f9930ca5419b3…

MALICIOUS

PDF

87.9 KB Created: 2021-09-15 15:58:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-27
MD5: 3b1b659fef138edff11f69a0580ea0e0 SHA-1: 8469c496343d7cb9291b0dd65fd0e021c793d61b SHA-256: 4f8f9930ca5419b3a9e77c9531e273c25c5d98e6eca34fc83ac699b9f84703c5
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF sample was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic suggests it functions as a link farm, directing users to numerous distinct, potentially malicious domains. The embedded URLs and the nature of the heuristics point towards a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://vanrun-it.nl/userfiles/files/89137176094.pdf In PDF document text
    • http://0985028898.kad.tw/kads/ckfinder/userfiles/files/1311771290.pdfIn PDF document text
    • http://vodnik48.ru/content/file/56459414273.pdfIn PDF document text
    • http://ampletrekking.com/userfiles/file/22240407862.pdfIn PDF document text
    • http://queensparkview.com/image/upload/File/57343761470.pdfIn PDF document text
    • http://zamdq.com/filespath/files/20210906215513.pdfIn PDF document text
    • https://nvsrolko.org/ckfinder/userfiles/files/zugag.pdfIn PDF document text
    • https://gruppopolidori.com/upload/image/file/95984513255.pdfIn PDF document text
    • https://spvi.cn/filespath/files/20210906203114.pdfIn PDF document text
    • https://brillimet.com/uploads/files/202109120153178832.pdfIn PDF document text
    • https://mallncart.com/userfiles/files/koratesadodane.pdfIn PDF document text
    • https://edenestates.com/ckfinder/userfiles/files/tonoluzosaxusifa.pdfIn PDF document text
    • http://bearings-home.com/userfiles/file/vodesevixeranudapiferekuv.pdfIn PDF document text
    • http://sjhtractor.com/d/files/bajezozeji.pdfIn PDF document text
    • http://afghansolar.com/userfiles/file/wamobideno.pdfIn PDF document text
    • http://louisefarmersmith.com/admin/ckeditor/ckfinder/userfiles/files/40259722532.pdfIn PDF document text
    • https://cortopolis.ar/userfiles/file/tiwoxopetu.pdfIn PDF document text
    • http://apex-architect.ru/images/file/bumopasiwukudogu.pdfIn PDF document text
    • https://equator-maritime.com/userfiles/file/nanuwojunewowatumazo.pdfIn PDF document text
    • https://shindah.com/images/ckeditor_img/files/tajilelodomanijoragegi.pdfIn PDF document text
    • http://kiajihlava.cz/UserFiles/File/81480139503.pdfIn PDF document text
    • https://dichvuhappyhouse.com/upload/files/82888226289.pdfIn PDF document text
    • https://voziky-paletove.cz/mctree.cz/pictures/other/files/waxaxamutupomukotunom.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=sonic+4+episode+2+thd+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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ca49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA49 25500 bytes
SHA-256: 9223cbb69bea7a5edeadef3677147086887d1eb440c182f22e614f9543b685a5
font_01_sfnt_off0001097b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1097B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012192.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12192 10828 bytes
SHA-256: 1ed83743ecd9b33cfcd70bdc6f64994c3405a2406239770a4d297afaa0cbf7ad
font_03_sfnt_off00013a8c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A8C 16456 bytes
SHA-256: f75cbc17297a647c1b4be74948f5402474c1b7223277d09206554fac532d2e0d