Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5ceb3ca15fcd379…

MALICIOUS

PDF

75.6 KB Created: 2021-10-08 00:10:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 803d775173a6199f046f7acf7a8b47cf SHA-1: cb784f6689824baa073d4ce24c78924351c42b65 SHA-256: b5ceb3ca15fcd37966329d9e99b2e33a55b5ad36036f0e3f2a9354fc3d9e934b
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous other PDF files hosted on various domains, many of which appear to be compromised CMS upload directories. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is unreadable binary data, suggesting it's not intended for direct user interaction but rather as a container for malicious links.

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://byecook.com/ckupload/files/bomajiwabok.pdf
    • https://perfecthospital.org/ckfinder/userfiles/files/29627297399.pdf
    • https://dasyueshan.org/userfiles/file/wezatitixuba.pdf
    • https://misbahelmudii.org/ckfinder/userfiles/files/79264852789.pdf
    • http://wxbeimei.cn/upload/ckimg/files/202110072045148484.pdf
    • http://dribblebar.pl/userfiles/file/kadirilu.pdf
    • http://www.tenniscanberra.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613376e960129---fipirexoxe.pdf
    • https://festivaldelmaridaje.com/sgi_userfiles/userfiles/files/vazitafajof.pdf
    • http://4x4autok.hu/userfiles/files/wixelokuzamegigekakup.pdf
    • http://idevoz.rs/files/wuwogozunikofupej.pdf
    • http://knipia.com/userfiles/file/98456288457.pdf
    • http://www.premiumimport.nl/ckfinder/userfiles/files/33016109220.pdf
    • http://kindervakantieweekdeurne.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1615aa70f11144---lunujoregakavifimaposatu.pdf
    • https://qigoodteam.com/uploads/files/202109042056437060.pdf
    • https://amoslodge10.org/ckfinder/userfiles/files/35855033527.pdf
    • https://sunwayhk.com/louis/STARKGROUP/ckfinder/userfiles/files/talefoduvosexegaru.pdf
    • http://www.goataxiservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/16147a341eb316---36076222023.pdf
    • https://penzion-pod-rozhlednou.cz/img/file/vilibimakimisozefed.pdf
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613570a7bb525---27767556093.pdf
    • https://gtijsr.com/userfiles/file/57081679163.pdf
    • http://www.aceitunasdelguadalhorce.es/ckfinder/userfiles/files/76175180542.pdf
    • https://factorysales.com/userfiles/files/juzotivazimuburekuko.pdf
    • https://aiwcecckolkata.org/FCKeditor/file/20714119503.pdf
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16150e36411e8f---12834282048.pdf
    • http://www.meglobalinc.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1613988ea8e9b1---fadijomamasanowotulovil.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=different+type+of+hardware
    • 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_off0000c3e7.bin
ab6f70c4936f4b3618cfa96db894cf46f63b5cc755e731259fe1047e56d2b7b2
pdf-font-stream PDF embedded font (sfnt) at offset 0xC3E7 17336 bytes
font_01_sfnt_off0000f0aa.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF0AA 16792 bytes
font_02_sfnt_off000108c1.bin
4032e23ffc3406843a6e4d9ea67882a8309afffe3e1fe4909291dc5bdb82860d
pdf-font-stream PDF embedded font (sfnt) at offset 0x108C1 10584 bytes