Malicious PDF — malware analysis report

Static analysis result for SHA-256 21a8158221a4e0fb…

MALICIOUS

PDF

96.4 KB Created: 2021-06-25 16:32:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 56569d9fc0c3de0b5a8bed5d60abbaf9 SHA-1: 50dfc3fdd44ae93477ec24ba285c1afae0d38fd1 SHA-256: 21a8158221a4e0fb9f8c1afacc5555574369f82f5b71253c505cc4746cba98f6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URIs and links to compromised CMS upload storage, suggesting it is part of a link farm designed to redirect users to malicious sites. The presence of embedded URLs and the nature of the heuristics point towards a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9946

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://coretry.ru/uplcv?utm_term=drudge+in+a+sentence PDF link annotation
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/jjngkdck3cijesssmur3pt6485/44803786020.pdfIn PDF document text
    • https://hssipm.com/wp-content/plugins/super-forms/uploads/php/files/28f442641691ce66cd257254072a2622/jejizutib.pdfIn PDF document text
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/160861bc0119ab---69441376551.pdfIn PDF document text
    • http://brukbet.com/user_images/file/91698605096.pdfIn PDF document text
    • https://ltssinternational.com/res/wysiwyg/file/gajigosufakoxafajewos.pdfIn PDF document text
    • http://abapaposentados.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ca19921257e---tubozeva.pdfIn PDF document text
    • http://jinohair.com/upload/files/dunovexo.pdfIn PDF document text
    • http://bajajsports.com/userfiles/file/8987827059.pdfIn PDF document text
    • http://abacusnancy.com/userfiles/file/32726501127.pdfIn PDF document text
    • http://syarmarka.ru/userfiles/files/52181880034.pdfIn PDF document text
    • http://zgkimsteszew.pl/img/upload/files/5931204696.pdfIn PDF document text
    • http://carrollcountylawyers.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/guxinuxigiwix.pdfIn PDF document text
    • http://c-amc.com/upload/files/23854765207.pdfIn PDF document text
    • https://napraforgohotel.hu/upload/file/rekudo.pdfIn PDF document text
    • https://www.autodepotperformancegroup.ca/wp-content/plugins/super-forms/uploads/php/files/lpeegm69mulogcfi9fglje1bgc/68206989202.pdfIn PDF document text
    • https://www.gs-gleichmann.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a74e0c0ebbd---34847589108.pdfIn PDF document text
    • https://inncredel.com/uploads/tuluxud.pdfIn PDF document text
    • http://heilpraxis-pankow.de/wp-content/plugins/formcraft/file-upload/server/content/files/160878998a8b91---xuvizuwojabozelobigoviba.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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_005_off000117ea.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x117EA 19544 bytes
SHA-256: 38153ad73fc5c1cc9f32680a0f6f89a0abd8f6ccc7b4e757c61883907dfb6d65
font_00_sfnt_off0000daa0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAA0 10480 bytes
SHA-256: f010762881628bf2438490d6d5de9a8729566a856642c759ea68317fd41c0130
font_01_sfnt_off0000f263.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF263 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010a70.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A70 3464 bytes
SHA-256: a8161c2f5ba9235eb51b4fcc43b6bb219725019365cb8d38f9ec25dfe5ce54ff
font_04_sfnt_off00013947.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13947 22948 bytes
SHA-256: 684bfa86edb33778667ce425d4315b69bff3537aaffb288eaebff53bd0a3c2e9

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