Malicious PDF — malware analysis report

Static analysis result for SHA-256 b357a4e9a936c002…

MALICIOUS

PDF

83.3 KB Created: 2021-09-23 09:33:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 27b25b2b500662ea9b1de7555cf3dab3 SHA-1: ebb7d6aee21116428e6d0d3042ac53dfb59f504e SHA-256: b357a4e9a936c0029a80acfb21133a902b818ea2de76869e9792d46d35529ede
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It contains numerous URLs, many pointing to compromised CMS uploads and disposable hosting, suggesting a link farm designed to obscure the ultimate destination. The presence of external URIs and link farm heuristics strongly suggests an attempt to lure users to malicious sites, likely as part of a phishing campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 http://thcsnguyenvanhuyen.hoaiduc.edu.vn/ckfinder/userfiles/files/jofugovuxojonaxipozipume.pdf In PDF document text
    • http://willajarmar.pl/userfiles/file/75809752962.pdfIn PDF document text
    • https://liguecasa.mmsfoot.com/stock/file/40751174131.pdfIn PDF document text
    • https://hunglivet.com/uploads/files/202109170429415886.pdfIn PDF document text
    • http://4yoga.by/pics/files/wamon.pdfIn PDF document text
    • https://ferado.vn/userfiles/file/47193247070.pdfIn PDF document text
    • http://eskuvoiiranytu.hu/blog/file/94726146636.pdfIn PDF document text
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/6b9fac18aea49199e1b35760804fcd9e/foxufariweferuxikubita.pdfIn PDF document text
    • https://infrapanel-alegjobbfutes.hu/userfiles/file/kebelikefalaxalalinifom.pdfIn PDF document text
    • http://ks-system.co.uk/ckfinder/userfiles/files/wepologopupunu.pdfIn PDF document text
    • http://josephfellerlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/nixegiwikukikufawek.pdfIn PDF document text
    • http://sinojjacob.com/userfiles/file/54123079650.pdfIn PDF document text
    • http://wingmanresearch.com/userfiles/files/popaziwusamuximonakupo.pdfIn PDF document text
    • http://tjsijiqing.com/ckfinder/userfiles/files/2021/0918/12312800ce9839edcbe48cefebe4ceb1.pdfIn PDF document text
    • http://monteconsultants.com/image/upload/File/mofawadogiret.pdfIn PDF document text
    • http://abwjefferson.com/uploads/files/65513995576.pdfIn PDF document text
    • http://mai-colle.jp/userfiles/file/wuboxelopemesonuposuku.pdfIn PDF document text
    • https://btegypt.com/file/63922647284.pdfIn PDF document text
    • https://vickers-electronics.co.uk/wp-content/plugins/super-forms/uploads/php/files/3a88d1ea16db8533fc85b2552046ba27/90840324523.pdfIn PDF document text
    • http://car-zone.sk/data/data/file/28305017979.pdfIn PDF document text
    • http://abogarestudio.com/userfiles/file/93187809766.pdfIn PDF document text
    • https://abisspaandboutique.com/nbloom/fckuploads/file/belesinuxuboganilesoname.pdfIn PDF document text
    • http://bastola.org/userfiles/file/92136212984.pdfIn PDF document text
    • https://www.isnb.co.uk/wp-content/plugins/super-forms/uploads/php/files/35c1436a2c2da98692534601ca57b251/geluwabemunebunesifas.pdfIn PDF document text
    • http://area100impianti.it/userfiles/files/zidakejivutimiju.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=gta+mobile+no+verificationPDF 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_off0000de33.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE33 18620 bytes
SHA-256: e1b040cea88576208de4d2a72521b178113605f950480057750ae4f1736488d0
font_01_sfnt_off00010f3e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F3E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012755.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12755 10576 bytes
SHA-256: 7d02cc6c2669fb44198c1686a8836f4fa3f9f9632d866990c9108f5598e700c7

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