Malicious PDF — malware analysis report

Static analysis result for SHA-256 8db4c8bdf498122a…

MALICIOUS

PDF

69.2 KB Created: 2021-09-24 21:34:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e36bb173485fe52b62196b5702356807 SHA-1: 3a54214b20e1e98dedd1ad87d8b6be858ec16ae1 SHA-256: 8db4c8bdf498122a636f096e0c2bbbaac235cda3dec0819894fb86d9d0e60fbf
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised WordPress upload storage 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 distributing further malware. Although no scripts were explicitly extracted, the PDF structure and embedded links are indicative of a malicious document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://krisoc.ru/uplcv?utm_term=mirror+phone+to+laptop+using+usb
    • https://suprastoc.ro/userfiles/file/56510332876.pdf
    • http://www.radio-kum.si/data/files/lemonipizuzegunapile.pdf
    • https://accu-split.com/userfiles/files/taxosukasova.pdf
    • https://rosebankprimary.co.za/inc/ckfinder/userfiles/files/53892460991.pdf
    • http://epmresearch.org/userfiles/files/jabiximedawapi.pdf
    • http://dental-forum.ru/userfiles/file/82473249973.pdf
    • http://www.rosabrockenhaus.ch/ckfinder/userfiles/files/75717168426.pdf
    • https://pmms-online.com/assets/file/26969247126.pdf
    • http://photonart.nl/phpcmsys/file/11355809568.pdf
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/161426ceeb7c73---82116819189.pdf
    • http://domkomplekt34.ru/attachments/file/tujiruxugixotidamapa.pdf
    • http://traditionsradio.com/wp-content/plugins/super-forms/uploads/php/files/b7ff243ae6e24db2819d94abd60da3b7/lagewutirobifevulexuw.pdf
    • https://www.enviedecrire.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e7b664f345---pikosaziwujupezokosalo.pdf
    • http://thechitay.com/uploads/userfiles/file/32962035886.pdf
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141de318f908---7842753700.pdf
    • https://sv-fin.ru/wp-content/plugins/super-forms/uploads/php/files/43bc406b102b5930089858731433c7cb/37833437428.pdf
    • https://corpus.bg/files/fck/file/82045140912.pdf
    • http://dom-2000.ru/ckfinder/userfiles/files/29886425500.pdf
    • https://alpinismbihor.ro/app/webroot/files/userfiles/files/malir.pdf
    • http://sziszolg.hu/editor_up/xipekaremogadezixuwele.pdf
    • http://nusratali.com/userfiles/files/tokejo.pdf
    • http://karaokejdi.com/ckfinder/core/connector/php/upload/files/kilugekekife.pdf
    • http://jucal.es/images/file/repaxewegidikepix.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b112.bin
81151e667feb01a6ba90ef07eb33e4315b94ce669f51c449ec8a7bd74a99d00f
pdf-font-stream PDF embedded font (sfnt) at offset 0xB112 10764 bytes
font_01_sfnt_off0000c991.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xC991 16792 bytes
font_02_sfnt_off0000e1a3.bin
6e7c1413e5d298a049ef8df7fa58a455bf9f83d3ce5d01a7b7b69e008d975b94
pdf-font-stream PDF embedded font (sfnt) at offset 0xE1A3 14948 bytes