Malicious PDF — malware analysis report

Static analysis result for SHA-256 de603c4ea5e7baa5…

MALICIOUS

PDF

82.2 KB Created: 2021-09-11 19:11:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 2805d47f6622ed4d9d29d889a6049354 SHA-1: 35bd5329d555039fa0944bb740504fc3a34f18e6 SHA-256: de603c4ea5e7baa5522f6534a34e8549ddcd58fcef2dd70f816c80217a7fefc1
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware delivery. No scripts were extracted, but the presence of multiple external links is the primary indicator of compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://ruiguoex.com/upfile/files/2021/09/03/81094409677.pdf
    • http://www.hgekc.com/media/userfiles/file/wutopelerinafugosevo.pdf
    • http://rkmaster.ru/uploads/files/sigakil.pdf
    • http://w.scenekunstskolen-efteruddannelsen.dk/ckfinder/userfiles/files/73152047442.pdf
    • https://adikkedua.com/contents/files/6471997908.pdf
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130942d78c1a---2082166528.pdf
    • https://foodsafebox.com/ckfinder/userfiles/files/pipobovajuxukovevori.pdf
    • https://www.hungarianassociation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f96af55759---sisejajaxaduzofuxileg.pdf
    • http://zsmnowakowski.pl/userfiles/file/tirukum.pdf
    • https://malinaionescu.ro/userfiles/file/pufagokekadiz.pdf
    • http://shanghaiqingchen.com/upload/files/sagukiro.pdf
    • http://bright-mineral.com/uploadfile/file/2021091105004890.pdf
    • http://optimaglobal.net/ckupload/files/39792305903.pdf
    • http://solo-reisen.com/media/images/file/rugasumawexojuvobi.pdf
    • https://edu-mate.kr/_UploadFile/Images/file/fixovitub.pdf
    • http://www.nanodrywash.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613543b05509d---2819348698.pdf
    • http://jgweld18.com/UploadFile/file/20210910083133106.pdf
    • https://olterus.com/contents/files/retidusavutijumu.pdf
    • https://boyanbolyarski.com/userfiles/file/72647314587.pdf
    • https://newsale.linyn.mobi/upload/ckeditor/pages/files/71267201816.pdf
    • http://urgentcarepb.com/userfiles/file/wijida.pdf
    • https://staging-info.sharkovinkom.com/sharkovinkom.com/ckfinder/userfiles/files/dulomafudodus.pdf
    • http://thecargonepal.com/userfiles/file/kepemudore.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=stop+starting+start+finishing+pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000daea.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDAEA 16792 bytes
font_01_sfnt_off0000f301.bin
af499f854a99161f7f625f640f3556aef3efe0dc81ff1a99d0f6e670f7c9ba9b
pdf-font-stream PDF embedded font (sfnt) at offset 0xF301 10672 bytes
font_02_sfnt_off00010b23.bin
3a5d42cc8ba6dc64a6744b91ba8ff2467017f27623baa160e6a26a2f011e89d4
pdf-font-stream PDF embedded font (sfnt) at offset 0x10B23 18684 bytes