Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4f23cfb352d7d64…

MALICIOUS

PDF

80.3 KB Created: 2021-09-18 22:12:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 3f79f0cadc347d495ce260188d72fc23 SHA-1: 2f49e53e6728571e6e5e506967beeea1bcb60a7c SHA-256: a4f23cfb352d7d64c6edd977f879e9cca2c87264b5bc3b1fa86edaeeac5a4a8b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. No scripts were extracted, but the structure and URL patterns are indicative of a malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://safarekhoob.ir/basefile/safarekhoobir/files/gukometujamexug.pdf In PDF document text
    • https://mystruggle.uk/indigo/ckfinder/userfiles/files/58203559610.pdfIn PDF document text
    • http://pebyte.com/wp-content/plugins/super-forms/uploads/php/files/0gjddc3ipaah02v1d1ufkjlu0b/xulibivesudek.pdfIn PDF document text
    • http://multiseal.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/16135f3acb504b---gasalumilokanevuvawomusib.pdfIn PDF document text
    • https://aluminiosarla.com/userfiles_arla/files/xevevomaleminufoka.pdfIn PDF document text
    • https://spheresignal.com/app/webroot/userfiles/files/92941879159.pdfIn PDF document text
    • https://torbay.ru/images/uploads/file/26964239930.pdfIn PDF document text
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/161420eac097dd---vesopupuv.pdfIn PDF document text
    • https://cashofferoregon.com/wp-content/plugins/formcraft/file-upload/server/content/files/161406c988cca0---lezibexilisorufesevel.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/gumidosukovekolejagepe.pdfIn PDF document text
    • http://nppmaudaha.in/ckfinder/userfiles/files/madek.pdfIn PDF document text
    • https://www.gryf-wet.pl/ckfinder/userfiles/files/vakiruva.pdfIn PDF document text
    • http://kubak-ubezpieczenia.pl/userfiles/file/jiwoxiluvulagafakiki.pdfIn PDF document text
    • http://agisma.ru/files/pages/files/88632873772.pdfIn PDF document text
    • http://luxcottage.ru/stroykamen/userfiles/files/ganag.pdfIn PDF document text
    • http://apmnir.ro/fckfiles/file/taremoxa.pdfIn PDF document text
    • http://teenmag.cz/userfiles/file/65868141938.pdfIn PDF document text
    • http://hydrem.ru/images/file/98648207820.pdfIn PDF document text
    • https://taiwan-tiaya.com/upload/tiaya_official/files/54009106420.pdfIn PDF document text
    • http://fulepmark.hu/nyebu/fulepmark/userfiles/file/ladofojumajobavopikipuzi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=pokewalk+ios+downloadPDF 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_off0000d86e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD86E 10220 bytes
SHA-256: fdc2f46c32b3180a7b567f85680a1e457ffc00e319783c33b5e47f22b2252927
font_01_sfnt_off0000ef85.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF85 17064 bytes
SHA-256: 1600a3e6e4ee07ae3a0605adf1aafa251ef39cc8ffcba3c7ac13d7e535a5da8d
font_02_sfnt_off00011bb0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BB0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1