Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f42b1c7b495f720…

MALICIOUS

PDF

69.7 KB Created: 2021-09-18 19:00:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: e5f21ab61dfeafd334cb9b8599a2beaf SHA-1: 16250ee4789258c414fbef1695f1bf5127f41b70 SHA-256: 4f42b1c7b495f720354241f6e066a3ef7570cb7e8ea40bd5455cb5aa92815772
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was detected as malicious by ClamAV and a machine learning classifier. It functions as a link farm, containing numerous URLs pointing to other PDF files hosted on compromised websites. This suggests a phishing or malware distribution campaign, where the initial PDF serves as a lure to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://nomylo.ru/uplcv?utm_term=tinto+brass+yts PDF link annotation
    • http://jamoncup.es/wp-content/plugins/formcraft/file-upload/server/content/files/16140c02b63f29---vedunu.pdfIn PDF document text
    • http://candybeauty.vn/upload/files/tuwudu.pdfIn PDF document text
    • https://ruiguoex.com/upfile/files/2021/09/11/jonitanesiruxorugiwin.pdfIn PDF document text
    • http://banquat.com/userfiles/files/zurewagikekemir.pdfIn PDF document text
    • https://urology-andrology.com/userfiles/file/46299883084.pdfIn PDF document text
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/hoccck8rq89tiv3grbtjub5knj/5853231891.pdfIn PDF document text
    • https://gad-elhak.com/userfiles/file/vujemekupujepox.pdfIn PDF document text
    • http://thedewakohchang.com/image/upload/File/170124592.pdfIn PDF document text
    • https://gpagroup.in/wp-content/plugins/formcraft/file-upload/server/content/files/161403c8743712---95207383055.pdfIn PDF document text
    • http://sage-chem.com/image/files/20210911_220452.pdfIn PDF document text
    • http://studiomanzetti.it/userfiles/files/pufumixifixej.pdfIn PDF document text
    • http://tiwtactic.com/userfiles/files/85366558862.pdfIn PDF document text
    • http://bestbelly.org/content/files/files/bojosonopesepejadev.pdfIn PDF document text
    • https://maintogelonline.info/contents/files/gekojire.pdfIn PDF document text
    • http://ghibms.com/userfiles/files/tisobuvugapopojonafi.pdfIn PDF document text
    • http://short-story.ru/upload/file/nevogibolaruxotute.pdfIn PDF document text
    • http://tyros-club.de/userfiles/file/63765652693.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161431d4bc4c7c---16463760314.pdfIn PDF document text
    • http://195exim.com/datas/files/65842309411.pdfIn PDF document text
    • http://www.themixchange.com/userfiles/files/22300264342.pdfIn PDF document text
    • http://ymmicro.com/files/files/6445239707.pdfIn PDF document text
    • 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_off0000ad53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAD53 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c56a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC56A 10140 bytes
SHA-256: d33892653ee72001019922960bf57f893153033dd7f42ac36e14a8ebd1da62af
font_02_sfnt_off0000dc3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC3A 17492 bytes
SHA-256: f9f664b6778ce0a18866c1b862684b46a6946ddbbe4907143fadb0fa2fcd9936