Malicious PDF — malware analysis report

Static analysis result for SHA-256 816fb9dad79fd3a4…

MALICIOUS

PDF

80.8 KB Created: 2021-09-17 01:09:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: ffaf4f064b99473849bb05bb862c7ef3 SHA-1: 8cab919dbb66d5494a5beb7ec601c16d9fe39171 SHA-256: 816fb9dad79fd3a42be8a3252056d4b8488252b9c13e2cc78b4a570205388326
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple embedded URLs, with several heuristics indicating a link farm and random URL generation, suggesting a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly indicate malicious intent. While no scripts were directly extracted, the PDF structure and embedded URIs are indicative of a phishing lure, likely leading to further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://infrive.ru/uplcv?utm_term=diablo+1+for+android
    • http://www.jobsincrete.gr/images/_user_na/file/dikilupovenosuvu.pdf
    • http://gotoippc.com/ckfinder/userfiles/files/62200221641.pdf
    • https://trexanh.net/upload/files/25247947732.pdf
    • https://eliteswimmingpoolsinc.com/wp-content/plugins/super-forms/uploads/php/files/tk0kn35b6nbkks470thm3adqh1/12554102505.pdf
    • https://bodymason.com/user_uploads/files/titaji.pdf
    • http://agnieszkapawlik.com/userfiles/file/51315829490.pdf
    • http://togclick.com/media/userFckfiles/file/21754339545.pdf
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/tamab.pdf
    • https://www.campacinter.com/image/upload/File/wegit.pdf
    • http://verduciautodemolizioni.it/userfiles/file/xituzizapunudive.pdf
    • https://iaido-iaijutsu.ru/userfiles_exc/muroda.pdf
    • http://ort168.com/upload/ckeditor/files/5460710858.pdf
    • https://tatsolarlight.com/uploads/files/piganizenelif.pdf
    • https://widepolymers.com/userfiles/file/rozetafa.pdf
    • http://huarui-bio.com/upload/files/48319059774.pdf
    • http://studiorinaldibedin.eu/userfiles/files/wetove.pdf
    • http://lookupagency.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613b95e2b8554---53711879688.pdf
    • http://bjhtdszdh.com/v15/Upload/file/202192105569637.pdf
    • https://em.heephong.org/ethnicminorities/cmsadmin/ckfinder/files/72033366912.pdf
    • https://cuichi177.com/uploads/files/202109160757162298.pdf
    • https://ciar.vn/uploads/image/files/70869906445.pdf
    • http://tienphat.vn/imagesflashupload/file/bezivuwim.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d587.bin
b146b9ac4d559b59bd42ddfdbbb25d652deb1b1b62dc357907eb1d49170e8e9e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD587 10140 bytes
font_01_sfnt_off0000ec37.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEC37 16792 bytes
font_02_sfnt_off00010449.bin
31a6618b8436fc190ef73f805ca221e4582fd865642ae29913487c0daa9a17f7		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10449 19036 bytes

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