Malicious PDF — malware analysis report

Static analysis result for SHA-256 257383a875906396…

MALICIOUS

PDF

74.8 KB Created: 2021-09-13 06:33:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 537ca4d277def5830ac29db1b697278b SHA-1: 4cdfa3db2d30ccc1e4986491939fa88a7a4aec11 SHA-256: 257383a875906396c78cb99c1d0a8de63e84863828e46fddf3eb3326be961b0c
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was identified as malicious by ClamAV and an ML classifier, with heuristics indicating embedded JavaScript and a link farm. The embedded JavaScript likely serves to execute malicious code or redirect the user. The link farm points to multiple domains, some of which are hosted on compromised CMS platforms, suggesting an attempt to obscure the final destination or leverage trusted domains for malicious purposes. The presence of embedded JavaScript and the nature of the URLs strongly suggest an attempt to deliver a secondary payload or phish for credentials.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://klwas.org/userfiles/images/file/famexojoforen.pdf In PDF document text
    • http://parkwestresidences.com/wp-content/plugins/formcraft/file-upload/server/content/files/161363c3a532f3---vusilora.pdfIn PDF document text
    • http://tetrafluoro.com/upload/files/58932489211.pdfIn PDF document text
    • https://beldaoyun.com/calisma2/files/uploads/26967264600.pdfIn PDF document text
    • http://vinhthuan.vn/upload/files/voboxi.pdfIn PDF document text
    • http://rowadhr.com/app/webroot/upload/files/72903038912.pdfIn PDF document text
    • http://esenkardeslerinsaat.com/resimlerfiles/jebuxorapelewinikemip.pdfIn PDF document text
    • https://xn--fct8ml6mwue.tw/uploads/files/85753630662.pdfIn PDF document text
    • http://www.ih-consultant.com/ckfinder/userfiles/files/55934574255.pdfIn PDF document text
    • https://ajur.rest/uploads/userfiles/file/vaxapupulux.pdfIn PDF document text
    • https://www.northamericatalk.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133ed79d5b05---59847042205.pdfIn PDF document text
    • http://104408017.linker.tw/files/6874348249.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-9-5/20210905000303177207.pdfIn PDF document text
    • http://pensjonatagat.pl/userfiles/file/ramuxumetatubibapoxog.pdfIn PDF document text
    • http://nhatrangpalacehotel.com/app/webroot/upload/files/fupotejotavikejewe.pdfIn PDF document text
    • https://hnhaa.com/userfiles/tnejp/files/mofinivakaguzosono.pdfIn PDF document text
    • https://netshopnepal.com/userfiles/file/toridoxukuwetis.pdfIn PDF document text
    • http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/c9o4krebgq753iqs4oh62nebt4/mawanexuleforaboreror.pdfIn PDF document text
    • https://sklepbonus.eu/userfiles/file/92137786681.pdfIn PDF document text
    • http://ucg-eg.com/userfiles/file/84906593508.pdfIn PDF document text
    • http://xszhuhai.com/uploadfiles/files/sejamufager.pdfIn PDF document text
    • https://cmf8.ir/data/file/25833963309.pdfIn PDF document text
    • https://vinaconexmec.vn/uploads/news_file/34607495479.pdfIn PDF document text
    • https://akilanews.com/ckfinder/userfiles/files/48323457374.pdfIn PDF document text
    • http://zopos.zohukum.com/ckfinder/userfiles/files/putamijedibudilapederoza.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=gangstar+3+miami+vindication+apkPDF 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://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_off0000c436.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC436 16884 bytes
SHA-256: 55bce30e4c7b8b4fe024f63d2495f3f12a20f3ea3b2ddd60a55e66de8f851cef
font_01_sfnt_off0000efa9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFA9 11048 bytes
SHA-256: cd04d859d35acfcc7bd9c162a51d2973f5a251a4e2c79773329d846e2fa807b7
font_02_sfnt_off00010951.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10951 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1