Malicious PDF — malware analysis report

Static analysis result for SHA-256 139f779f8dcdf053…

MALICIOUS

PDF

86.8 KB Created: 2021-09-08 19:53:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 9d6dbd3c953777d46b8268be1cc9d67d SHA-1: 4fcb231011af912ca0fbda7416154dd520d828e2 SHA-256: 139f779f8dcdf0537224fe0b413688e538e2ea49c9e79d538dc6bb48c40408a4
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and a large number of external URIs, many of which point to disposable domains. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM specifically flags this behavior as a link farm on disposable hosting, indicating a likely phishing or malware distribution attempt. The ML classifier and ClamAV detection further support the malicious nature of the file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://starroadchina.com/userfiles/file/gifogopumukubigujudil.pdf In PDF document text
    • http://heathrowairporttaxi.website/userfiles/file/nilabufovokolev.pdfIn PDF document text
    • http://sfalojistik.com/userfiles/file/bakelitokajiwimex.pdfIn PDF document text
    • http://xn--80aaa1acmiejxr6d7fg.xn--p1ai/data/files/mobeleduvudelekud.pdfIn PDF document text
    • http://diysmart.net/userfiles/file/15652978782.pdfIn PDF document text
    • http://pactolous.hu/upload/file/nekagowaworiz.pdfIn PDF document text
    • http://rlmlaw.com/images/edit_images/file/34166643436.pdfIn PDF document text
    • https://damiel.eu/userfiles/file/pirilap.pdfIn PDF document text
    • http://yyfxsw.com/upload/files/lisuxisag.pdfIn PDF document text
    • http://bridgeonlaw.com/filespath/files/20210906120931.pdfIn PDF document text
    • http://sino-web.net/filespath/files/20210908044806.pdfIn PDF document text
    • https://rotterdampools.com/contents/files/kizodepupisugelaweg.pdfIn PDF document text
    • https://dondepodemosir.com/userfiles/file/fomixakum.pdfIn PDF document text
    • https://mannerfeltdesignteam.se/ckfinder/userfiles/files/goxikipuxelusawuderovew.pdfIn PDF document text
    • http://yunnanyingxiang.com/ckfinder/userfiles/files/73703225398.pdfIn PDF document text
    • https://digireg.nu/upload/67417286256.pdfIn PDF document text
    • https://studiecarriere.it/uploads/file/tulavuvobevuf.pdfIn PDF document text
    • https://www.hungarianassociation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ed5a3b3953---34416652728.pdfIn PDF document text
    • http://skyrun-arser.com/js/fckeditor/editor/filemanager/connectors/php/connector.php/upfiles/file/2109071519079223737l2r1g.pdfIn PDF document text
    • https://bawaniint.com/ckfinder/userfiles/files/64675783110.pdfIn PDF document text
    • https://matricula.netlandschool.cl/files/mumelajuze.pdfIn PDF document text
    • http://huerural.com/uploads/image/files/1967400735.pdfIn PDF document text
    • https://satuldelut.ro/ckfinder/userfiles/files/71050043980.pdfIn PDF document text
    • https://toananhmedical.com/uploads/files/81003215272.pdfIn PDF document text
    • http://ozgu-yapi.com/firma/files/75565727418.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=comparative+literature+theory+and+practice+pdfPDF 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_off0000edcc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDCC 17760 bytes
SHA-256: 4b8648d7bf5d851143699814e5947fcdfbe4b8926a279e38e6ba599e59478fcc
font_01_sfnt_off00011bf9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BF9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013410.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13410 11028 bytes
SHA-256: 9bc6a01e5e08ff0b3a056fb771e00c370deefa3d12072e4a6bb8c555e4c4ed82