Malicious PDF — malware analysis report

Static analysis result for SHA-256 6c917279f2b832b7…

MALICIOUS

PDF

77.0 KB Created: 2021-10-06 22:59:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 42b44d843a7a274b022db95044037eaf SHA-1: ae297327a8922f7971eb692ca5523ea119967808 SHA-256: 6c917279f2b832b7c2a555b105de9e9dd458d92cedcb63b229e342370d176f29
156 Risk Score

Malware Insights

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

The sample was detected as a phishing trojan by ClamAV and flagged by an ML classifier. It functions as a link farm, with numerous embedded URLs pointing to compromised WordPress sites and other domains, likely to redirect users to malicious content. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using disposable hosting for these links, further suggesting malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.6733

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://krisoc.ru/uplcv?utm_term=and+nor+gates PDF link annotation
    • http://www.nuricomuvakfi.org/wp-content/plugins/super-forms/uploads/php/files/f90v3kh9d5l8bgku7ajgmkn3e5/86977003848.pdfIn PDF document text
    • http://myepres.com/HotelEstimator/userfiles/file/gosagekomajodob.pdfIn PDF document text
    • https://ohcsi.com/ckfinder/userfiles/files/jagotariduruzaw.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/1613b629a0f4c9---riwawupibog.pdfIn PDF document text
    • http://cravaluos.com/ckfinder/userfiles/files/63923867161.pdfIn PDF document text
    • http://ks-system.co.uk/ckfinder/userfiles/files/vofogifigibosev.pdfIn PDF document text
    • http://puebloexec.com/userfiles/file/20887061995.pdfIn PDF document text
    • https://miamiuniquelimo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16154566993652---virurofirosaxututoku.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614550dd33f17---94686923256.pdfIn PDF document text
    • http://eskuvotoszkanaban.hu/editor_up/bazuteku.pdfIn PDF document text
    • http://casaatlantida.com/userfiles/file///56699623058.pdfIn PDF document text
    • https://speakingparrot.com/upload/ckfinder/files/53195578667.pdfIn PDF document text
    • https://italvaping.com/file/minomixanavenijavito.pdfIn PDF document text
    • https://www.rath-catering.de/wp-content/plugins/formcraft/file-upload/server/content/files/1615953897cd90---94777497629.pdfIn PDF document text
    • https://adrfarysz.pl/userfiles/file/90333419033.pdfIn PDF document text
    • http://bagiez.com/userfiles/file/31044302078.pdfIn PDF document text
    • http://vegasoft.hr/wp-content/plugins/formcraft/file-upload/server/content/files/161352ba5bec1e---wekegodapuwisuxan.pdfIn PDF document text
    • http://caphegiabao.com/upload/fck/file/93131750119.pdfIn PDF document text
    • https://cradlegold.com/wp-content/plugins/super-forms/uploads/php/files/h9dv39k2hrks72nsaq892f4ht8/mevazomojajatuj.pdfIn PDF document text
    • http://thingsantiquesla.com/userfiles/files/pokowuxune.pdfIn PDF document text
    • http://kooijobs.in/ckfinder/userfiles/files/totawexorikezojejokopexi.pdfIn PDF document text
    • http://kingswaytyres.com/project/kingsway/uploads/file/kajopiva.pdfIn PDF document text
    • http://maraulsan.com/ckfinder/userfiles/files/karuvajapoxugod.pdfIn 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_off0000d225.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD225 17612 bytes
SHA-256: d6782fc678bbcb08b1b6c0c2a5a4b178933d1aae89c231d3c3620d30f56967b3
font_01_sfnt_off0000ffbd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFBD 10268 bytes
SHA-256: a382d9ace555d86ca105f96aafd9b6c510f3c365835ce25699f2fe7ab8cd6a1e
font_02_sfnt_off000116ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x116CA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1