Malicious PDF — malware analysis report

Static analysis result for SHA-256 633a98a92ff6326a…

MALICIOUS

PDF

82.8 KB Created: 2021-08-11 13:21:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 9458caba8e9abab02babc95c1c376fec SHA-1: 044cc7c76bc21bb86b36bb3ebcc35de16a670279 SHA-256: 633a98a92ff6326ab0a11d992c27342d2245cfff36f8124580cf387c04a89bc4
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 are part of a link farm hosted on potentially compromised or disposable domains. Heuristics indicate these links are designed to direct users to external sites, with one specific URL pointing to a compromised WordPress upload. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

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 https://catamma.ru/uplcv?utm_term=histology+book+for+medical+students+pdf PDF link annotation
    • https://bimstudioinc.com/media/files/xixobasoveseluriba.pdfIn PDF document text
    • http://ginzaoakland.com/uploads/files/85914261927.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae34a8e05ce---wetulunizelabose.pdfIn PDF document text
    • http://leoclubmarsala.it/userfiles/files/4522126381.pdfIn PDF document text
    • http://www.tecnotrefg.it/wp-content/plugins/formcraft/file-upload/server/content/files/160851f4e41a27---29516895245.pdfIn PDF document text
    • http://akifkasaboglu.com/esatfisek/images_upload/files/75238009244.pdfIn PDF document text
    • https://sanmuabancongty.vn/images/content/files/wazogubamibazumajujin.pdfIn PDF document text
    • http://an-ocn.ru/ckfinder/userfiles/files/3591783748.pdfIn PDF document text
    • http://amdind.com/userfiles/file/12866034246.pdfIn PDF document text
    • http://collegedelunion.com/clients/76066/File/95958566886.pdfIn PDF document text
    • http://securitydirect.it/wp-content/plugins/super-forms/uploads/php/files/cb0871c5b645dea290eb4bea611e06fd/vifefexasajisem.pdfIn PDF document text
    • https://sanxuattrucauthangkinh.com/Images_upload/files/93882032199.pdfIn PDF document text
    • https://nnt52.ru/userfiles/file/bajinilozub.pdfIn PDF document text
    • http://cosmik-kinoteatr.ru/sadm_files/83056226636.pdfIn PDF document text
    • http://yongqingtech.com/d/files/wojazukuwuwupunib.pdfIn PDF document text
    • https://cspdental.com/wp-content/plugins/super-forms/uploads/php/files/bd784b0b082ff04fefedf4992da00827/6315405626.pdfIn PDF document text
    • http://apcmagon.com/userfiles/lajeravujedofusijezatiwum.pdfIn PDF document text
    • http://elementsgogreen.com/userfiles/file/jupasawomu.pdfIn PDF document text
    • http://iphysiology.ru/upload/kowabafikovavinujite.pdfIn PDF document text
    • https://aliencosmicexpo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091f2b2cd1f4---bilozozunemotavitaposu.pdfIn PDF document text
    • http://riph.pl/userfiles/file/jorurivanujadexewiz.pdfIn PDF document text
    • http://china-baby-clothes.com/d/files/rewevolenurapopobodawar.pdfIn PDF document text
    • http://vetcasatenovo.it/userfiles/files/sizukeresetonunat.pdfIn PDF document text
    • https://www.energetisch-therapeut-estie.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160ba3cab86515---92688661273.pdfIn PDF document text
    • https://www.sudburyhighspeedinternet.ca/wp-content/plugins/super-forms/uploads/php/files/670f5fe2d0d5d31b889708737ab2b0a1/86058819979.pdfIn PDF document text
    • http://seventyfirstclassof69.com/clients/60772/File/wodudog.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_off0000dec7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEC7 11400 bytes
SHA-256: 3de5a5e28ba8220895a0b551d10ad812102e8456fce1cfbeeb697a334e010c06
font_01_sfnt_off0000f946.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF946 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011158.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11158 17264 bytes
SHA-256: 6219f31d74a0fe46dabfa98bfdc78e78860f4a91675d139855d7d361007ecb7d