Malicious PDF — malware analysis report

Static analysis result for SHA-256 55ed29b874dac928…

MALICIOUS

PDF

74.6 KB Created: 2021-09-10 05:14:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: f78e89fe1d6ba9c1f4b848d8f62a72df SHA-1: 7be29075440ac79f8b7bb0c5aa2fc3454a91b5bf SHA-256: 55ed29b874dac928c86c7fac5e9d5a869dcf3865c21b3f804e17787c3e1e3d3b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file is identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Static analysis reveals it functions as a link farm, containing numerous URLs pointing to external PDF files, many hosted on compromised CMS uploads. The document body is heavily obfuscated, but the presence of multiple PDF link farm heuristics and external URI firings strongly suggests a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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 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 http://laptopcuhaiphong.vn/upload/files/96873574491.pdf In PDF document text
    • https://dla-pracownika.pl/pliki_user/File/zivuralozoxebukewip.pdfIn PDF document text
    • http://doingthing.com/downloads/blog/geust/files/96032317365.pdfIn PDF document text
    • http://fuhua.tumujike.com/assets/upload/files/202109032121182403.pdfIn PDF document text
    • http://poledance-chrudim.cz/files/file/xesexojunasulukifikazad.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/365vol12ajv5srrhmf76io0ock/fubagatetuzer.pdfIn PDF document text
    • https://ezokniga.com/uploads/file/80221563983.pdfIn PDF document text
    • http://pulsrmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133e4c0e0ccb---bemul.pdfIn PDF document text
    • https://funbugs.ie/files/file/xewima.pdfIn PDF document text
    • http://moveisgarciadigital.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161348c0e374f3---67605905153.pdfIn PDF document text
    • http://plenerowe.kbo.pl/ckfinder/userfiles/files/61832581318.pdfIn PDF document text
    • http://bscsaoner.in/ckfinder/userfiles/files/18993373747.pdfIn PDF document text
    • https://fcksa.com/ckfinder/userfiles/files/50478901793.pdfIn PDF document text
    • https://icon-studios.com/userfiles/file/burovosulajawovibexakefo.pdfIn PDF document text
    • https://arabadvertise.com/userfiles/files/kekolisizudememetar.pdfIn PDF document text
    • http://balaton.varosom.hu/userfiles/files/50736036525.pdfIn PDF document text
    • http://mya1fc.com/files/ckuploads/files/buwajusa.pdfIn PDF document text
    • https://muratay.nl/userfiles/file/87935114077.pdfIn PDF document text
    • http://donghobaoan.com/uploads/files/lamipenojija.pdfIn PDF document text
    • http://thepokewave.com/uploads/files/36539253956.pdfIn PDF document text
    • https://saint-florentin.charcutier-traiteur.fr/ckfinder/userfiles/files/lowutoxeseje.pdfIn PDF document text
    • http://infracsap.hu/files/file/69346211142.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=new+headway+advanced+fourth+edition+answer+keyPDF link annotation
    • 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_off0000b909.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB909 18828 bytes
SHA-256: 7ad53ac1099da4ba6201c3796c8da68a8f75860ec5268c0e30372b1f4d70c878
font_01_sfnt_off0000e94d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE94D 10964 bytes
SHA-256: 8b8a9fef39a5f82fff2afd145cefa371524cc4c3afb96432a5d01b38445faed9
font_02_sfnt_off000102c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102C5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1