Malicious PDF — malware analysis report

Static analysis result for SHA-256 f73346b4f7ed1f98…

MALICIOUS

PDF

77.8 KB Created: 2021-10-06 04:11:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: d5cad76b05472ef2fd794004a957b9a4 SHA-1: 2977f2d668c3ce4d6760e971e784f275bee03fac SHA-256: f73346b4f7ed1f9855e5d1c063bd9a6fc8f5e444c2c2bc5005a5f508e9077e2f
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ClamAV and an ML classifier, exhibiting characteristics of a link farm. Multiple heuristics indicate the presence of external URIs and links pointing to compromised CMS upload storage and disposable hosting. The document body is heavily obfuscated and appears to be malformed, suggesting it is not intended for human readability but rather to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

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://synerhu.ru/uplcv?utm_term=infection+control+coordinator PDF link annotation
    • https://gadd-asso.org/userfiles/file/50965964832.pdfIn PDF document text
    • http://zentrumok.com/userfile/files/pimamobedobukolizafux.pdfIn PDF document text
    • https://cremeconferences.com/wp-content/plugins/super-forms/uploads/php/files/f668461995fe3ad8e2b5c30f0c5a9d5d/wevegeraluferokusodal.pdfIn PDF document text
    • https://macleanpinesdrivingschool.com.au/wp-content/plugins/super-forms/uploads/php/files/0d531ae4385131bd1eceed743cf257cb/39929438804.pdfIn PDF document text
    • http://mesterteto.hu/userfiles/file/37396940764.pdfIn PDF document text
    • http://www.startservis.sk/novy/ckfinder/userfiles/files/8700699580.pdfIn PDF document text
    • http://myapartment.de/web/editor/files/vuvubutimegigib.pdfIn PDF document text
    • http://exima.kr/userData/board/file/pesanurejedixis.pdfIn PDF document text
    • http://eltprof.ru/userfiles/file/vawen.pdfIn PDF document text
    • https://kopari.hu/files/file/gefezaniwasikawutuzu.pdfIn PDF document text
    • http://www.masozilina.sk/ckfinder/userfiles/files/49502167409.pdfIn PDF document text
    • https://rajakeempat.com/contents/files/53051586948.pdfIn PDF document text
    • http://snbedu.com/uploadfile/file///2021090108492228.pdfIn PDF document text
    • https://costarica4d.com/contents/files/93902330345.pdfIn PDF document text
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/2c970dc1a8a6250d8aa42b29d4df131d/30486900086.pdfIn PDF document text
    • http://dc-a0dcf319a153.breakthroughsport.com/userfiles/files/98033243395.pdfIn PDF document text
    • http://portaldeaquidauana.com.br/ckfinder/userfiles/files/tunatajupak.pdfIn PDF document text
    • http://cheers-gifts.com/userfiles/62546137521.pdfIn PDF document text
    • http://amidoux-peintures.com/ckfinder/userfiles/files/dabugutemasidel.pdfIn PDF document text
    • http://bakersfield.thepokeluau.com/uploads/files/todixaleviniwa.pdfIn PDF document text
    • http://ulsantour.com/FileData/ckfinder/files/20210908_911CF9A1EEA53ACB.pdfIn PDF document text
    • http://avanti-kuhni.ru/upload/files/pefat.pdfIn PDF document text
    • http://tvcsoltau.de/userfiles/file/nafijuvabajaxezaxarugedaf.pdfIn PDF document text
    • https://artcorner-fiberglass.com/userfiles/files/sigetokorutagu.pdfIn PDF document text
    • http://agriturismocorteerbatici.it/userfiles/files/zikatapamow.pdfIn PDF document text
    • https://vresponse.net/userfiles/file/40157483006.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_off0000cdec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDEC 17304 bytes
SHA-256: 06cb539a48481692f1f72e0d8aabbd8f3a45266c74e7aac112ea5b911e00df8b
font_01_sfnt_off0000fa07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA07 10252 bytes
SHA-256: 29a6a5b531e7f72089849ad1c003f87128c4a12cb593fc0a828fe28dfda7847e
font_02_sfnt_off0001112a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1112A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1