Malicious PDF — malware analysis report

Static analysis result for SHA-256 558cd55c57174e15…

MALICIOUS

PDF

86.7 KB Created: 2021-09-08 05:16:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 3d8239b4f525b9bdac117c610c562048 SHA-1: 5e144caea1e5f1d83560089131c5863f7c7acd10 SHA-256: 558cd55c57174e15160aba394ecfdbad5aae449e56a6b111848083994122c0e1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links to external websites, many of which are hosted on compromised CMS platforms or disposable hosting, suggesting a link farm used for phishing or malware distribution. The PDF structure itself is also flagged for containing duplicate object bodies, which can be used to obfuscate malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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 https://gangwontaxi.com/FileData/ckfinder/files/20210817_0C68AB651934AB86.pdf In PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/nkcer43lve218t3l2g36a5bhld/96377584304.pdfIn PDF document text
    • https://leavingcare3plus.ch/userfiles/files/tutixibupanegelaweviw.pdfIn PDF document text
    • http://archiprojektai.lt/app/webroot/uploads/userfiles/files/bewexalozafulusu.pdfIn PDF document text
    • http://scenekunstskolen-efteruddannelsen.dk/ckfinder/userfiles/files/sufematunifixiv.pdfIn PDF document text
    • https://haps.company/wp-content/plugins/super-forms/uploads/php/files/uu97a1i3jspjih2crv7rdo7em3/lisoma.pdfIn PDF document text
    • https://bayardplaza.co.uk/wp-content/plugins/super-forms/uploads/php/files/4cu65sbhl91hmn54v88qu965bk/69927126096.pdfIn PDF document text
    • https://quatden.vn/webroot/img/files/30888193886.pdfIn PDF document text
    • http://ambvet-trefontane.eu/userfiles/files/74053618766.pdfIn PDF document text
    • https://mamproducciones.es/wp-content/plugins/formcraft/file-upload/server/content/files/160c02f6cab992---podivoniwolijujemam.pdfIn PDF document text
    • https://fnb-concepts.com/images/uploads/files/ratopuwoxonag.pdfIn PDF document text
    • http://prasongp.com/file_media/file_image/file/47784151320.pdfIn PDF document text
    • http://savvyais.com/userfiles/file/fenuvapuvar.pdfIn PDF document text
    • http://talentfuturesservices.com/sharpinstitute/images/files/jelitadug.pdfIn PDF document text
    • http://manavpublicschool.org/manav/userfiles/file/majasofavox.pdfIn PDF document text
    • http://akinmedical.com/uploads/file/43657547175.pdfIn PDF document text
    • https://www.costaverde.it/wp-content/plugins/formcraft/file-upload/server/content/files/1609e83591b7d3---82876539553.pdfIn PDF document text
    • http://hy-concrete.ru/d/files/regimoruxupolimit.pdfIn PDF document text
    • http://barrarioservicos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607031c4911ab---78341939147.pdfIn PDF document text
    • https://www.yoursurveysurveyors.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1608f12aa90d37---77023245706.pdfIn PDF document text
    • http://progfin.pl/userfiles/file/32520249253.pdfIn PDF document text
    • http://yoron.net/up/files/52051553019.pdfIn PDF document text
    • http://nd-58.ru/wp-content/plugins/super-forms/uploads/php/files/9403cd9cf68eafa99dbee18dd62b9a81/xageb.pdfIn PDF document text
    • http://recviem.ru/img/upload/zijowunuvoguta.pdfIn PDF document text
    • http://sciencevier.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070027e1c789---juruw.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=the+business+model+innovation+pattern+cards+pdfPDF 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_off0000ec33.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC33 11152 bytes
SHA-256: 43526beaa32a3275ff9a6e18f0123515fdf59ff3816dfd0987f4448a56c04ce0
font_01_sfnt_off000105d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105D8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011dea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DEA 18280 bytes
SHA-256: f2bfee744984719eee30a1f25a281f963d0a15308582efa64480dce2857e4244

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