Malicious PDF — malware analysis report

Static analysis result for SHA-256 87878f42abce83be…

MALICIOUS

PDF

87.3 KB Created: 2021-09-12 09:37:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: eeb86d150d458fc822a514fa3b908135 SHA-1: 542f0459a2627b9b5c938ec5e0ebb1eb27700d1c SHA-256: 87878f42abce83be0e09abf28eced8e09bc01eaa253c58ea909901a82f05aab1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to potentially compromised or disposable hosting sites. The primary purpose appears to be redirecting users to external content, likely for phishing or to download further malicious payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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 http://firsttimehomebuyerstudy.com/images/file/semudi.pdf In PDF document text
    • https://jurvamartin.com/userfiles/file/wokodasalukasofijiga.pdfIn PDF document text
    • https://sikahaiphong.com/images/news/files/15963246045.pdfIn PDF document text
    • http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133b6e0e6823---63674190572.pdfIn PDF document text
    • http://cathugo-yachts.de/res/wysiwyg/file/76343688206.pdfIn PDF document text
    • http://mwbright.com/upload_fck/file/2021-9-3/20210903185005352619.pdfIn PDF document text
    • http://clevio.biz/fckUpload/file/8293613155.pdfIn PDF document text
    • http://altinay-law.com/images/file/napofuzomunexebabisakuli.pdfIn PDF document text
    • https://obermeyer-modemarkt.de/upload/file/7504970265.pdfIn PDF document text
    • https://gelblighting.com/userfiles/files/varuwome.pdfIn PDF document text
    • http://www.mtpartnersfl.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139253d8321f---17852379395.pdfIn PDF document text
    • https://gameclub.by/uploads/files/95297608966.pdfIn PDF document text
    • http://karaokejdi.com/ckfinder/core/connector/php/upload/files/xegalepem.pdfIn PDF document text
    • https://metricgroup.it/uploads/file/41432261125.pdfIn PDF document text
    • http://cdwy028.com/uploadfile/file/20210909132734.pdfIn PDF document text
    • http://novosib-sport.ru/ckfinder/userfiles/files/vorojarinosame.pdfIn PDF document text
    • https://danielfelber.ch/userfiles/file/belix.pdfIn PDF document text
    • https://fnb-concepts.com/images/uploads/files/64384407658.pdfIn PDF document text
    • https://activsport.ro/userfiles/file/41689655289.pdfIn PDF document text
    • http://tomaszskiba.com/userfiles/file/fukafawoxamotufidiker.pdfIn PDF document text
    • http://fmafirm.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/kiluwuf.pdfIn PDF document text
    • http://willtorock.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d2d74b01f4---buronon.pdfIn PDF document text
    • http://smartmedicaleg.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132af4ac47fd---68793457845.pdfIn PDF document text
    • http://hrzservices.com/uploadfiles/file/voxarowipudalaruxi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=my+hero+academia+season+5+episode+11+releasePDF 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_off0000e48d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE48D 22228 bytes
SHA-256: 7415d15e02439b841c0bfd84174588ae6cbe9d45e2fbae5aa1f0d28f98183dd0
font_01_sfnt_off00011e14.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E14 10972 bytes
SHA-256: 3682422d40d784642d394fcc2cd2c56b26c3f35f1ef3a06d6b30a49df8390e9f
font_02_sfnt_off0001376f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1376F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1