Malicious PDF — malware analysis report

Static analysis result for SHA-256 aa00a3865d85fe86…

MALICIOUS

PDF

85.9 KB Created: 2021-09-20 07:18:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: cbb9d157616ce6b78720fac369814ecc SHA-1: ad0b0beb60fb6fbe89f6bdcf0e48f70ea0ab06d7 SHA-256: aa00a3865d85fe86b6f7eefd59f03ed488876ddd20a162179c1650180f5b16cd
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to other PDF files hosted on suspicious domains, indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. While no scripts were explicitly extracted, the PDF structure and link farm behavior are indicative of a spearphishing attachment used to lure victims to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9952

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://krisoc.ru/uplcv?utm_term=windows+7+latest+iso+download PDF link annotation
    • https://inprovitbrasil.com/ckfinder/userfiles/files/80279201854.pdfIn PDF document text
    • http://ingmarcofaedi.com/userfiles/files/16703655036.pdfIn PDF document text
    • http://srtprogetti.eu/userfiles/files/xezugipolilasesawere.pdfIn PDF document text
    • https://callmarkinvestments.fortunekenya.com/callmark/files/fojorawa.pdfIn PDF document text
    • https://songhong-thudo.com/img/files/rewug.pdfIn PDF document text
    • http://emirates-offshore.com/uploads/image/file/61152921389.pdfIn PDF document text
    • http://ambulatorioveterinariocigliano.com/userfiles/files/71856898298.pdfIn PDF document text
    • http://twfindia.in/userfiles/files/14955144889.pdfIn PDF document text
    • http://ncdesign.it/userfiles/files/69481662871.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1612fb7d2bbc6a---revapazovabuwovelukudojup.pdfIn PDF document text
    • https://www.autopsrus.com/ckfinder/userfiles/files/kofifozijav.pdfIn PDF document text
    • http://pajurioverslas.lt/ckfinder/userfiles/files/kokisipisatoxefide.pdfIn PDF document text
    • http://daglichtfilters.nl/ckfinder/userfiles/files/zubixuxedenulamazugama.pdfIn PDF document text
    • https://alwillislifecenter.org/ckfinder/userfiles/files/20414593070.pdfIn PDF document text
    • http://nhuaduongnhapkhauaz.org/upload/files/difiguvaxovu.pdfIn PDF document text
    • http://perevodvnegiloifond.ru/pict/file/86313319125.pdfIn PDF document text
    • http://tprcindia.com/ckeditor/ckfinder/userfiles/files/zilezazos.pdfIn PDF document text
    • http://socialbomjesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/16143315d26125---lasufudonujevisexu.pdfIn PDF document text
    • https://poolpoint.be/uploads/file/12525351198.pdfIn PDF document text
    • http://ipmarketing.net/FCKeditor/editor/filemanager/connectors/userfiles/file/28674672309.pdfIn PDF document text
    • http://pr-jam.com/ckfinder/userfiles/files/59949308655.pdfIn PDF document text
    • http://lnhaihui.com/userfiles/file/20210902132236_91786688.pdfIn PDF document text
    • https://crcnueva.naturasoftware.com/uploads/images/files/92578255901.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_off0000dd91.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD91 18100 bytes
SHA-256: c80bc665cc2364929329283f88bb501cf7a678c77d9b8efe194383f33adafc4f
font_01_sfnt_off00010cd5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CD5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000124ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x124EC 14784 bytes
SHA-256: 858ad0a14803347d1b2d2429cefd96d0bf4a383945e0adae376c5e46d94b1e2c