Malicious PDF — malware analysis report

Static analysis result for SHA-256 88ff4fcb75c3c54a…

MALICIOUS

PDF

73.1 KB Created: 2021-09-02 22:09:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 6f90a4e99a46ce453dedcc95aff9c89d SHA-1: 38b3be4d460960e08d8bf3b3014c540c61b28772 SHA-256: 88ff4fcb75c3c54ae7dea14188c245b2bb77bb58ce3e34897e35665eb82f2aee
156 Risk Score

Malware Insights

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

The PDF document contains numerous external URIs and link farm heuristics, indicating it is designed to redirect users to potentially malicious websites. The ClamAV detection and ML classifier strongly suggest malicious intent, likely for phishing or malware distribution. No scripts were extracted, and the document body was unreadable, but the presence of compromised CMS upload links and disposable hosting reinforces the malicious nature of the linked resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://synerhu.ru/uplcv?utm_term=el+alquimista+libro+completo+pdf+descargar PDF link annotation
    • https://rugsinc.in/UserFiles/files/nudexokovuw.pdfIn PDF document text
    • https://prosperitas.be/data/assets/file/fopazuda.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/d07698385e862c959be29d7f489dde6f/28124156807.pdfIn PDF document text
    • http://www.mmalappeenranta.com/tiedostot/files/20677383965.pdfIn PDF document text
    • https://rfcorporation.net/wp-content/plugins/super-forms/uploads/php/files/f2a9166851bcf067980dab9dc648a412/93342530996.pdfIn PDF document text
    • http://fiumaradelsossio.it/userfiles/files/77988604239.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f9c78341441---83657821330.pdfIn PDF document text
    • http://goref.ru/files/file/gefuzupe.pdfIn PDF document text
    • https://veritiesinstitute.com/wp-content/plugins/super-forms/uploads/php/files/61da8245853e115619e8f29f06ef7a2c/tegijetanemapodofuvexik.pdfIn PDF document text
    • https://bykevin.com/wp-content/plugins/super-forms/uploads/php/files/0b8e3c7062015147b0a55c2a05a67574/8764847793.pdfIn PDF document text
    • http://graphicon.hu/wp-content/plugins/formcraft/file-upload/server/content/files/160756ff61c672---zosimudu.pdfIn PDF document text
    • http://saopauloairporttransfers.com/ckfinder/userfiles/files/30454434741.pdfIn PDF document text
    • http://thedewakohchang.com/image/upload/File/2288947526.pdfIn PDF document text
    • http://w.scenekunstskolen-efteruddannelsen.dk/ckfinder/userfiles/files/gefaxitakewedo.pdfIn PDF document text
    • https://technoculture.cz/admin/upload/file/1451284424.pdfIn PDF document text
    • https://www.lamuccacompany.com/wp-content/plugins/super-forms/uploads/php/files/1aadb58e5ce7465a9eb01a66373a8bbe/7826699103.pdfIn PDF document text
    • https://vsetinrally.cz/userfiles/file/23664245288.pdfIn PDF document text
    • http://backkwang.com/userData/board/file/norufonibavimekatap.pdfIn PDF document text
    • https://alihuata.com/userfiles/file/27138259718.pdfIn PDF document text
    • https://aspit.ro/imagini_ws/mosakukojap.pdfIn PDF document text
    • http://voorwindenotariaat.nl/app/webroot/files/ckeditor_files/files/rujeninozerivopato.pdfIn PDF document text
    • https://actor-conseil.com/files/file/doziga.pdfIn PDF document text
    • http://air-con.ru/upload/files/76157596207.pdfIn PDF document text
    • https://retake.dk/ckfinder/userfiles/files/vatipumakimujibolaxo.pdfIn PDF document text
    • https://mokhalasati.com/userfiles/files/72577981131.pdfIn PDF document text
    • 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_off0000bb09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBB09 16840 bytes
SHA-256: 5ba74fcf6d6b83d4ba9c00ae986e6be706af67908a9c398846fb03565a6a58d0
font_01_sfnt_off0000e4b3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4B3 11228 bytes
SHA-256: 670b5106228bdb5dd123cdd324e77037575911589f1b549d208adcf99d6baa19
font_02_sfnt_off0000fe4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE4D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1