Malicious PDF — malware analysis report

Static analysis result for SHA-256 3b9a0c840fc62521…

MALICIOUS

PDF

73.8 KB Created: 2021-09-04 20:36:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: dcd3419a3feaa48e40b795d6c1e2371e SHA-1: 342f1d3828716f1d306cc59c82c15ba982dd1753 SHA-256: 3b9a0c840fc625216332a7298ccbbeb5163b9e84e6d441f55d88072a8f2b0243
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by an ML classifier and contains numerous links to compromised WordPress sites, indicating it functions as a link farm. The presence of external URIs and link farm heuristics suggests the primary goal is to redirect users to potentially malicious content hosted on these compromised sites. No scripts were extracted, but the PDF structure itself is designed to facilitate this redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 5

  • 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://aliencosmicexpo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b504f5b071---81667422447.pdf In PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/160db5468bcfe9---15045946673.pdfIn PDF document text
    • http://www.nagsa.es/ckfinder/userfiles/files/nokilaxobag.pdfIn PDF document text
    • http://hurtmar.pl/Upload/file/voretiwebupu.pdfIn PDF document text
    • https://mrmusicfoundation.org/wp-content/plugins/super-forms/uploads/php/files/qhv2aat1ocrsfno55ah8epa4c5/7930280799.pdfIn PDF document text
    • https://hylyt.co/wp-content/plugins/super-forms/uploads/php/files/80f71f6423f18803ea3e073828d9b6c2/87811516107.pdfIn PDF document text
    • http://www.zav-mito.si/wp-content/plugins/formcraft/file-upload/server/content/files/160e2ed1e1e76c---zebat.pdfIn PDF document text
    • http://girc.ncue.edu.tw/ckfinder/ckfiles/files/11664183272.pdfIn PDF document text
    • https://promobryansk.ru/userfiles/files/volosilubodoviduno.pdfIn PDF document text
    • http://ymy-tea.tw/upload/files/86601355402.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/ufvucq9ar1psdhkhun2frtrcj1/62567381194.pdfIn PDF document text
    • http://bizwd.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073fc1064557---wesek.pdfIn PDF document text
    • http://lavalnerina.it/userfiles/file/58508130664.pdfIn PDF document text
    • http://yanartextil.com/firma/files/toverurara.pdfIn PDF document text
    • https://www.denisonlandscaping.com/wp-content/plugins/formcraft/file-upload/server/content/files/160dde3dd5be16---givexol.pdfIn PDF document text
    • https://big-cash.de/wp-content/plugins/super-forms/uploads/php/files/kki3eaj799jm6nk43mmn805ihm/76218373087.pdfIn PDF document text
    • http://kalkulacka-hypo.cz/userfiles/files/finiwonebopubowo.pdfIn PDF document text
    • http://hamlineparkplaza.com/assets/amund/ckfinder/userfiles/files/98986700923.pdfIn PDF document text
    • https://rajaunited.com/contents//files/zedofe.pdfIn PDF document text
    • http://golfvillageonline.com/userfiles/file/79926041047.pdfIn PDF document text
    • https://www.chauffeur-prive-nice.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16103db1125322---tojigowap.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607aa541c7dd2---51187926332.pdfIn PDF document text
    • http://weberstellen.ch/userfiles/file/26374177214.pdfIn PDF document text
    • http://chieucoingason.vn/files/jukimarezusan.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=dividing+decimal+numbers+by+10+100+and+1000+worksheetPDF 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_off0000bb56.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBB56 17120 bytes
SHA-256: 7e88bff63154ba58d697b6d05eac6f50a4f9729efdf1bd4d95cd2ebc8fa90039
font_01_sfnt_off0000e612.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE612 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fe29.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE29 11588 bytes
SHA-256: c22757bbc9dce49a479e60e4633ca60dbaa904fb03639bc2de308892750e7134