Malicious PDF — malware analysis report

Static analysis result for SHA-256 8b03143be968f4bb…

MALICIOUS

PDF

69.4 KB Created: 2021-09-24 18:53:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 6218fa6d4a2c10950489a00bc9e77504 SHA-1: 33d9462e6b5dfe10e32eca041530b50e89801d6b SHA-256: 8b03143be968f4bbea40e91980402f633cf583339b00c0376102de2a1ae34362
156 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ClamAV as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to disposable hosting or compromised CMS upload directories. The ML classifier also strongly indicated maliciousness. The primary attack pattern involves luring users to click on these links, likely leading to further malicious content or exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://qwert5.com/psum/admin/userfiles/file/55826769323.pdf In PDF document text
    • http://floral-design-lindgens.de/userfiles/file/tazixekuso.pdfIn PDF document text
    • http://sherwoodchambergolf.com/ckfinder/userfiles/files/nepolebuvuvudabibixevo.pdfIn PDF document text
    • https://home18.ru/wp-content/plugins/super-forms/uploads/php/files/4145f4560b0f3d8e15557f66193462c1/mamanonazeruli.pdfIn PDF document text
    • http://thietbikhachsanvinhhung1.com/upload/files/bonuzop.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/wekajuberuz.pdfIn PDF document text
    • http://www.ddu-hk.cz/ckfinder/userfiles/files/56893463767.pdfIn PDF document text
    • https://deshpanday.com/ckfinder/userfiles/files/jesepubedafetobenifulozef.pdfIn PDF document text
    • http://rallyteamwalraven.nl/file/fuwifujefavubapikekoninog.pdfIn PDF document text
    • http://dgxzz.com/uploadfile/file/58885782643.pdfIn PDF document text
    • http://www.ebsjosepirosamaria.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e24e167b7b---wusekogufit.pdfIn PDF document text
    • http://tokstar.com/_UploadFile/Images/file/38260204050.pdfIn PDF document text
    • http://1544-7419.net/upload/fckeditor/file/ditogasafutagemoxijon.pdfIn PDF document text
    • http://pwr-tech.ru/userfiles/file/84218522948.pdfIn PDF document text
    • https://osiindia.org/ckfinder/userfiles/files/56823088856.pdfIn PDF document text
    • http://www.linkkorea.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/1613ac42b84c3c---duxifaxavatumunase.pdfIn PDF document text
    • http://baobianhkhang.com/upload/files/76697252216.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/16145b5ea1a527---jekefogusozada.pdfIn PDF document text
    • http://ned.ru/uploads/files/vejobukan.pdfIn PDF document text
    • https://theloneranger.tv/clients/loneranger/ckfinder/userfiles/files/41155618312.pdfIn PDF document text
    • http://sithome.com/upfiles/file/20210906005949.pdfIn PDF document text
    • http://studioaeditecne.it/userfiles/file/98247986003.pdfIn PDF document text
    • http://an-professional.ru/img/files/file/xalemakusox.pdfIn PDF document text
    • https://jaurrieta.net/USERFILES_JAURRIETA/files/13765036552.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=video+cache+android+appPDF 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_off0000b1cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1CB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c9dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9DD 15012 bytes
SHA-256: 1a0df7ffb1309a4ece19db206c3a1b4919a638098cb527f5f6c9f442f8a043b5
font_02_sfnt_off0000ef34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF34 10268 bytes
SHA-256: e33c65a8670864bfe9f30dc90a73dd4f3078da77b733a7a9b68212e4a9e66e30