Malicious PDF — malware analysis report

Static analysis result for SHA-256 77a23fa9cb3f309f…

MALICIOUS

PDF

74.0 KB Created: 2021-10-21 00:35:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: 31703c330ca1be85f8c06316156a8585 SHA-1: 37d7f5f7c69eef2f51a51a166dd3b87b154923e8 SHA-256: 77a23fa9cb3f309f2688798fa13160ec9cb5f3df1e0b85b6a190ffde7fea410f
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which are associated with link farms and disposable hosting, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. Although no scripts were explicitly extracted, the PDF structure and URL patterns are indicative of malicious activity, likely spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://crysiq.ru/uplcv?utm_term=2020+maths+exam+paper+answers PDF link annotation
    • https://ceiling.holcom.vn/webroot/img/files/42207552861.pdfIn PDF document text
    • http://dlevitin.ru/fck_editor_files/files/lofero.pdfIn PDF document text
    • https://sirikulsteel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615dcbb884b96---26472021535.pdfIn PDF document text
    • http://www.libroparlatolions.it/backoffice/ckfinder/userfiles/files/fadizizefezu.pdfIn PDF document text
    • https://www.teppiche-waschen-hamburg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16133deab9e948---fosotunujabog.pdfIn PDF document text
    • https://interativacorretora.com/fotosempresa/files/mibalejalebedisigipi.pdfIn PDF document text
    • https://hyosung-gulf.com/uploads/file/45507444347.pdfIn PDF document text
    • http://sunkamalzemecilik.com/userfiles/file/bunusaloburujofujetase.pdfIn PDF document text
    • http://win-sonic.com/ck_imgs/files/25593555249.pdfIn PDF document text
    • http://strahyi.ru/images/file/kajobozikotuxap.pdfIn PDF document text
    • http://tentauto23.ru/ckfinder/userfiles/files/76286254284.pdfIn PDF document text
    • https://pfhotel.gr/ckfinder/userfiles/files/daluw.pdfIn PDF document text
    • https://virtrade.gr/userfiles_lybo/file/94267843503.pdfIn PDF document text
    • https://www.hkfew.org.hk/ckfinder/userfiles/files/vojelibimake.pdfIn PDF document text
    • http://mrcookie.tw/upload/editor/file/13112048391.pdfIn PDF document text
    • https://elmaga.lt/components/com_mijoshop/opencart/image/data/files/7378533455.pdfIn PDF document text
    • http://lienming-rubber.com/uploads/files/202109250044415378.pdfIn PDF document text
    • http://bctlorraine.org/userfiles/file/tipudetub.pdfIn PDF document text
    • https://observatoire-omic.org/documents/file/mogado.pdfIn PDF document text
    • https://communeouchamps.fr/userfiles/file/90956385771.pdfIn PDF document text
    • http://raffaelecavazzoni.com/userfiles/files/xujaludulitebitosubaj.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_off0000bd72.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBD72 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d584.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD584 17432 bytes
SHA-256: 547b1a499a79cfc1610720056aec87b4cfab8693b5d58ef2f2255b4d2675aef3
font_02_sfnt_off00010268.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10268 10592 bytes
SHA-256: 6f0305492558a2b70989de4740489a7dd2cca09846a81e2ff0077b043f766ea5

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