Malicious PDF — malware analysis report

Static analysis result for SHA-256 51f142b03af1c2a3…

MALICIOUS

PDF

81.3 KB Created: 2021-09-23 20:02:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 0af41cbedb778b509a3d49725e1a32a0 SHA-1: eeacb413f8d6712914ad68aaae7c2529a694bab7 SHA-256: 51f142b03af1c2a37c43050374361c715930d0362ddbc2a3dd557e8c3805c528
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to various domains, some of which are identified as compromised CMS uploads or hosted on disposable domains. The primary purpose appears to be directing users to potentially malicious content or phishing sites, consistent with a spearphishing attachment attack vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 https://crysiq.ru/uplcv?utm_term=bedste+videoredigering+til+android PDF link annotation
    • http://dribblebar.pl/userfiles/file/88190373043.pdfIn PDF document text
    • http://dietmoiquangle.com/webroot/img/files/72167219818.pdfIn PDF document text
    • https://www.lang-mayer.de/wp-content/plugins/formcraft/file-upload/server/content/files/16142c396e5516---96505624507.pdfIn PDF document text
    • http://donghozibistore.com/luutru/files/81847856449.pdfIn PDF document text
    • http://celesteandtorsten.wedding/images/file/tujezusax.pdfIn PDF document text
    • https://lwim-ouargla.dz/ar/files/luvegipazafilurazadikimow.pdfIn PDF document text
    • https://nolimitscenter.be/peausitive/images/FCKeditor/file/tuxixavelorazofujibukot.pdfIn PDF document text
    • http://grandviewgroupresort.com/upload/files/66827002207.pdfIn PDF document text
    • http://almar-bus.pl/userfiles/file/finelulubetewo.pdfIn PDF document text
    • http://nbnjl.com/userfiles/files/fojevugiw.pdfIn PDF document text
    • http://maynenkhiinverter.com/media/ftp/file/mokowedas.pdfIn PDF document text
    • https://bednidhitraders.com/userfiles/file/bigixavijojiguj.pdfIn PDF document text
    • http://hz-karavany.cz/ckfinder/userfiles/files/73426239030.pdfIn PDF document text
    • http://ancheng-medical.com/uploadfile/files/xinilopigot.pdfIn PDF document text
    • http://www.carolglassman.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134759fa7844---30869343846.pdfIn PDF document text
    • http://schubert-hh.de/image/file/defabakiporinuni.pdfIn PDF document text
    • http://movesearchesuk.com/userfiles/file/nixuvanodiv.pdfIn PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1614ca5cd82f41---bulidotul.pdfIn PDF document text
    • http://thietbiotovn.com/Images_upload/files/81664451562.pdfIn PDF document text
    • http://melvin.cz/data/57382117073.pdfIn PDF document text
    • http://an-professional.ru/img/files/file/83015268263.pdfIn PDF document text
    • https://corpeverest.com/ckfinder/userfiles/files/15291387898.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_off0000db6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB6B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f37d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF37D 16544 bytes
SHA-256: ea18652ce9613864aeea707a1a0c62d18e2f3da4de2f987dbf25c2455ae01652
font_02_sfnt_off00011e06.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E06 10540 bytes
SHA-256: 8b288f0b54284a0ca4089ca17d7bd62e28c59a3a302b2b8308294521b008c2a0