Malicious PDF — malware analysis report

Static analysis result for SHA-256 28b1498b8ad22a07…

MALICIOUS

PDF

84.3 KB Created: 2021-06-25 18:10:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a5d597e5193eac1afb230d1dc3f823dc SHA-1: 004cf10d42f857559572c38a33d3dadf17c4cb5c SHA-256: 28b1498b8ad22a07ebeeb6f914eec9b26e307537ab47ce135a820846c64aee2a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The sample is a PDF document identified as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many pointing to compromised WordPress sites or disposable domains, suggesting a phishing or malware distribution scheme. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a link farm strategy, and the PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristic highlights the use of compromised infrastructure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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://cructi.ru/uplcv?utm_term=dosage+calculations+a+ratio+proportion+approach+pdf
    • http://sakuragiramenandsushi.com/uploads/files/puxunibuwajo.pdf
    • https://dipinkrishna.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084215abfdfb---30215821259.pdf
    • http://www.tenniscanberra.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1606fce75248af---65535047841.pdf
    • http://cesnek-vysocina.cz/UserFiles/File/xidedogelalif.pdf
    • http://c2mag.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a4f5bc0bc97---bovivavifu.pdf
    • http://tykhestudiodesigns.com/clients/7/73/7311521ca682816632878891c231d107/File/29072623897.pdf
    • http://aelma.com/sites/default/userfiles/file/8713233427.pdf
    • http://www.combatsim.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160d1cd8fdaf31---lepawubevumamuvilajisok.pdf
    • https://thietkevuphong.com/uploads/image/files/51701205447.pdf
    • http://lotuscourtpune.com/wp-content/plugins/super-forms/uploads/php/files/beturi6rg8urnhuecbrfuiomj5/tafibigakenibotojoxozu.pdf
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a2daa5dd56a---66563639240.pdf
    • https://congchung7.com/upload/file/67684539062.pdf
    • https://imapcb.org/wp-content/plugins/super-forms/uploads/php/files/jejpj58apnc1kb5fln3h660hd7/megalapezamitexineritetel.pdf
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606f34092d5cd---72143080768.pdf
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609eec02c900d---52220661195.pdf
    • https://hacunamatata.ru/wp-content/plugins/super-forms/uploads/php/files/a0c8d227e2195812b833f4202ad4b5d6/284755358.pdf
    • https://www.phoenixdentalacademy.co.uk/wp-content/plugins/super-forms/uploads/php/files/aa3a2462b94e251af8f166546a6adae9/7280249225.pdf
    • http://kco.su/userfiles/file/pirexomosemizom.pdf
    • https://expungemyrecordnj.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608427fe8bdd6---76149392344.pdf
    • https://janeunchained.com/wp-content/plugins/super-forms/uploads/php/files/oogutekktcec2onsjn6at084u3/13175365962.pdf
    • http://thermogroup.ru/uploads/files/jububokebal.pdf
    • http://domusanna.it/userfiles/files/detebalaxijow.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_off0000e504.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE504 16792 bytes
font_01_sfnt_off0000fd16.bin
a8b0ad524c70cdfee0f8228adc42bc33c59a3b03bff485271bcf9bfa75256359
pdf-font-stream PDF embedded font (sfnt) at offset 0xFD16 17328 bytes
font_02_sfnt_off00012a95.bin
ab1bed2b9d4557d661d88c1135a73db64b9c55ba33beba341a9455e97ab781d7
pdf-font-stream PDF embedded font (sfnt) at offset 0x12A95 11000 bytes