Malicious PDF — malware analysis report

Static analysis result for SHA-256 8cc388a5caee80d1…

MALICIOUS

PDF

76.9 KB Created: 2021-09-19 10:42:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: f9e58be241ab2ac0e699d2cea8c87ed6 SHA-1: 9cc098cf530815b778180fdd2329f63f25c79d67 SHA-256: 8cc388a5caee80d15f2b431e0ec742f40bae38c937a46fb87b5b7d4e30a92cde
156 Risk Score

Malware Insights

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

The PDF was flagged by multiple heuristics as a link farm, with many URLs pointing to compromised or disposable domains. The ML classifier and ClamAV also identified it as malicious, likely a phishing or trojan delivery mechanism. Although no scripts were explicitly extracted, the nature of the link farm suggests an intent to redirect users to malicious sites, potentially for exploitation or credential harvesting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 http://vector-luczak.pl/new/fck_user_files/file/69758853235.pdf In PDF document text
    • http://rootbeadmill.com/upload_fck/file/2021-9-19/20210919060941823075.pdfIn PDF document text
    • http://land89.com/ckupload/files/27598019076.pdfIn PDF document text
    • http://ne-moloko.ee/wp-content/plugins/super-forms/uploads/php/files/dbf4266187010bd6a60635f3acf7c921/32038631798.pdfIn PDF document text
    • http://rfinshaat.az/userfiles/file/wuduxifuwajusanew.pdfIn PDF document text
    • https://clinicscrm.com/img/files/setazekarexojodap.pdfIn PDF document text
    • http://archetipoingegneria.it/userfiles/files/34476581488.pdfIn PDF document text
    • http://chanhbon.vn/media/ftp/file/pofobatubuk.pdfIn PDF document text
    • https://efsanepin.com/calisma2/files/uploads/ferukives.pdfIn PDF document text
    • http://tfh-filter.hu/_user/file/jemigitilewajikawuvewuv.pdfIn PDF document text
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/f704ae1a523dcc35ff34d236481ad28d/81819308379.pdfIn PDF document text
    • http://ijfbn.com/editor_up/27570428782.pdfIn PDF document text
    • http://westernmaki.com/uploads/files/68175186471.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613854dee708c---45696111564.pdfIn PDF document text
    • https://saikekanglun.com/filespath/files/20210906153241.pdfIn PDF document text
    • http://theeultimatenetworker.com/ckfinder/userfiles/files/2233047199.pdfIn PDF document text
    • http://grupafurman.pl/!mag2011/userfiles/file/54406247266.pdfIn PDF document text
    • https://hunghiephuylog.com/upload/files/sazemosavokibemime.pdfIn PDF document text
    • https://byocamacho.com/ckfinder/userfiles/files/95015989809.pdfIn PDF document text
    • http://sushigonewildtogo.com/uploads/files/newavobusire.pdfIn PDF document text
    • https://blagoustroystvo24.ru/ckfinder/userfiles/files/julekeseromukagedezataset.pdfIn PDF document text
    • https://lifesmart.ro/ckfinder/userfiles/files/wegexagudupovufunejewux.pdfIn PDF document text
    • http://www.britocunhaadvocacia.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/1613389ec6c26c---56563537255.pdfIn PDF document text
    • https://xn--64-mlcufjjaii0l.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/dfb1640362b56cf7c19271546493d60c/31244794236.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=siren+head+mod+for+minecraft+pePDF 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_off0000c845.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC845 10748 bytes
SHA-256: c6517a9209ae9a296512a3fe9f65f84c6d03cc73bb61f50fb87a822400157f80
font_01_sfnt_off0000e0c2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0C2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f8d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8D4 17356 bytes
SHA-256: 108c05d74624245178c6d5dc858eae363379a28a09f07407e0b3d96ab40b6046