Malicious PDF — malware analysis report

Static analysis result for SHA-256 cc479b4282a05643…

MALICIOUS

PDF

75.6 KB Created: 2021-09-17 09:28:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 1154743c116fbabcf43d4d4a1ac2df77 SHA-1: d525603c38f6b842f597e37616e0338b2d4f3b28 SHA-256: cc479b4282a05643edeb6b8aaaab079c58ffb043775a289bdeefb7376ef92f88
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm with numerous external URIs, including one pointing to krisoc.ru. The document body is heavily obfuscated, preventing a clear understanding of its specific lure, but the overall structure and URL patterns suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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=watch+wonder+egg+priority+online+free PDF link annotation
    • http://agcslohian.com/userfiles/file/53920445243.pdfIn PDF document text
    • https://ustunbilgisayar.com/userfiles/files/16815283247.pdfIn PDF document text
    • http://techscreening.com/userfiles/files/9521613197.pdfIn PDF document text
    • https://www.tzounakos-insurance.gr/ckfinder/userfiles/files/sosimufim.pdfIn PDF document text
    • http://www.ctnphrae.com/ckfinder/userfiles/files/natupo.pdfIn PDF document text
    • https://macauroommate.com/ckfinder/userfiles/files/53668700524.pdfIn PDF document text
    • https://bibonatura.com/ckfinder/userfiles/files/miweduxifefoziv.pdfIn PDF document text
    • https://www.wroclawmodelshow.pl/ckfinder/userfiles/files/99812560974.pdfIn PDF document text
    • https://www.displaysdirectaustralia.com.au/application/third_party/ckfinder/userfiles/files/patumugumufeta.pdfIn PDF document text
    • https://psihodesk.ro/ckfinder/userfiles/files/80417437266.pdfIn PDF document text
    • https://phm.vn/upload/files/34608629251.pdfIn PDF document text
    • http://hippodrome-compiegne.fr/www/uploads/file/45590249612.pdfIn PDF document text
    • http://pomodorolennep.de/gfx/userfiles/files/43893471951.pdfIn PDF document text
    • http://hasicimosnov.cz/foto/Image/file/mewazepidej.pdfIn PDF document text
    • http://cocoal.com/uploads/file/4508516549.pdfIn PDF document text
    • https://highfieldhousehotel.net/nbloom/fckuploads/file/zodarogutimafozakajubazeg.pdfIn PDF document text
    • http://gfzgt.ch/upload/file/dibupaxizizudesedip.pdfIn PDF document text
    • https://openkomm.yussfone-crm.com/userfiles/file/50436617279.pdfIn PDF document text
    • https://reazfarah.com/ckfinder/userfiles/files/bafos.pdfIn PDF document text
    • https://matricula.netlandschool.cl/files/84841378327.pdfIn PDF document text
    • https://pelicanfinancialnetwork.com/ckfinder/userfiles/files/12048254261.pdfIn PDF document text
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/0f283006ecba5a5b64a57bac04dff90b/28321728048.pdfIn PDF document text
    • http://xn--zb0bw3kv4s8mn.com/upload/fckeditor/file/lelawiroratumo.pdfIn PDF document text
    • https://oteaexpert.fr/cite_imgs/file/66645510295.pdfIn PDF document text
    • http://huynhgiabaohotel.com/uploads/FCK/file/bitavilanakutiweme.pdfIn PDF document text
    • http://dalnoboy.org/data/filestorage/upload/files/93275271192.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_off0000bfe1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBFE1 10924 bytes
SHA-256: da38a9184bed0f9c2e761ece6696c0bf46564fa3a815e796f132d8df5a5524f6
font_01_sfnt_off0000d8f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8F6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f108.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF108 18336 bytes
SHA-256: 78282ab49355029d19d447711d0efd8501e753a44781b5c650bed867dd9c1ef5