Malicious PDF — malware analysis report

Static analysis result for SHA-256 388431d83f44af57…

MALICIOUS

PDF

75.5 KB Created: 2021-09-16 04:25:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 08bcbaa5f072818f5272ff09f3979464 SHA-1: 644997e8c63720c32909d7558ee0700132c19b5c SHA-256: 388431d83f44af57b4af3d592bc296124934317d60579012ff08e58af91ae5ed
126 Risk Score

Malware Insights

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

The sample was detected by ClamAV as Pdf.Phishing.Trojan and an ML classifier flagged it with high confidence. It contains numerous embedded URLs, many pointing to PDF files on disposable or unknown domains, suggesting a link farm for SEO poisoning or malware distribution. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically indicates this behavior.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://vom-ragnaroek.de/uploads/file/65692783748.pdf In PDF document text
    • http://mizuho-co.net/file/ck/files/lijafato.pdfIn PDF document text
    • https://inprovitperu.com/ckfinder/userfiles/files/5146730542.pdfIn PDF document text
    • http://amtusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fdaa21448e---fedajewatogawawugof.pdfIn PDF document text
    • https://cuisinescartier.ca/upload/editor/file/ralopewujefowix.pdfIn PDF document text
    • https://miamivanservice.net/wp-content/plugins/formcraft/file-upload/server/content/files/1613407b77a3ee---95779193844.pdfIn PDF document text
    • https://perfecthospitals.org/ckfinder/userfiles/files/30661089351.pdfIn PDF document text
    • https://ichapps.com/ichapps/ckeditor-ckfinder-integration/uploads/files/33443278478.pdfIn PDF document text
    • https://irish-setter-zucht.info/ckfinder/userfiles/files/vadakifajomeri.pdfIn PDF document text
    • http://gyogytornasz.hu/editor_up/xirukumupukikamuret.pdfIn PDF document text
    • http://moretonassets.net/userfiles/67130682680.pdfIn PDF document text
    • https://gogift-it.com/userfiles/files/karazubuvelanemux.pdfIn PDF document text
    • https://osakaav.com/userfiles/files/didonowerenakexelatin.pdfIn PDF document text
    • http://jimsclub.net/new/board/img_tinfo/file/20210913140645.pdfIn PDF document text
    • http://plise.org/userfiles/file/70336872375.pdfIn PDF document text
    • https://metrosecuritynepal.com/assets/userfiles/files/pibak.pdfIn PDF document text
    • https://nguyenhungstone.com/uploads/image/files/37364375403.pdfIn PDF document text
    • http://t-p-fortune.com/userfiles/file/gosaso.pdfIn PDF document text
    • http://ainut.fi/userfiles/file/66283598200.pdfIn PDF document text
    • https://jjcfurnituremaker.com/userfiles/files/33172579296.pdfIn PDF document text
    • https://nmg.lv/img/uploads/files/28117929273.pdfIn PDF document text
    • https://butagallery.com/userfiles/files/41596116820.pdfIn PDF document text
    • https://bitree.com/ckfinder/userfiles/files/mavuxovafixonive.pdfIn PDF document text
    • http://xn----7sbev0bhje.xn--p1ai/images/news/file/79201756370.pdfIn PDF document text
    • http://massintech.ru/img/outer/files/wosunedobovonozoxapawomu.pdfIn PDF document text
    • https://bandai-k.com/userfiles/file/wipexajugegu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=pes+2019+iosPDF 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_off0000c575.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC575 10052 bytes
SHA-256: c0b48deecdbc99b14dc84a4f23e0b702630ad9da2ac653b8e1e210024f1cfe6c
font_01_sfnt_off0000dc07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC07 17240 bytes
SHA-256: a1ba81370f61f813303e9a680c0cdbe27d8bc60dd9d581eabb84ea8179960c85
font_02_sfnt_off00010885.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10885 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1