Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c8a481c813c83be…

MALICIOUS

PDF

85.4 KB Created: 2021-06-30 02:59:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b032d13c313dc8b5b02318d26685d908 SHA-1: 93f7538f2dafdd6689b5cd9bb28068bf2b6cb289 SHA-256: 5c8a481c813c83bece766990dfb2ac7d9f51f0e8b57392dfa431bd1ab55364e4
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous URLs pointing to various domains, many of which are hosted on compromised WordPress sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. The file's structure and numerous external links suggest it is designed to lure users to external resources, potentially for exploitation or credential harvesting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://www.sixteengrams.com/wp-content/plugins/super-forms/uploads/php/files/nhnco70lbtc0l3g8tqmetmpfh0/43998436207.pdf
    • https://na-nule.ru/wp-content/plugins/super-forms/uploads/php/files/trr08deatpehgcp1c3e1ktgku0/34249083783.pdf
    • http://simonhoirup.dk/userfiles/file/lomobafelarunijisarobofa.pdf
    • https://aftaplan.com/works/peepsparty/html/upload_files/file/jujeledes.pdf
    • http://planetamama.ru/files/file/45736897188.pdf
    • http://dabaizhongxue.com/upload_fck/file/2021-5-20/20210520112910832675.pdf
    • https://ppuhperspektywa.pl/files/edytor/file/xizonu.pdf
    • https://ludifrance.fr/userfiles/file/jemadir.pdf
    • https://www.hausbootgeiseltalsee.de/wp-content/plugins/super-forms/uploads/php/files/e713fptc8i40anq3kqbrh64vuc/16723818548.pdf
    • http://sy-smile.com/upload/files/65267600123.pdf
    • http://aiswaryamatrimonials.com/fck_uploads/file/womubinimupusiragina.pdf
    • http://www.nandomoraes.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ae7b4a8a6cf---56317753881.pdf
    • https://ols.lighting/wp-content/plugins/super-forms/uploads/php/files/e4bb1b9b996894d2ae567b516b3bfab0/pepibarudebupi.pdf
    • http://busangh.com/attfile/fckimg/file///202106023140_853210341.pdf
    • https://lescourailleurs.com/upload/editor/file/14550639271.pdf
    • http://altelaw.com/uploads/image/file/63592306326.pdf
    • http://korean-school.hu/hangul/userfiles/file/jegoxejatib.pdf
    • https://mamotato.ro/userfiles/file/bupamakovofirixig.pdf
    • https://b2cexpressdemo.com/userfiles/file/wedisugig.pdf
    • http://ledseoul.com/userData/board/file/73909339024.pdf
    • http://pphu-joanna.pl/fckpliki/file/vozalivilegivizojevejas.pdf
    • http://ldbell1965.net/clients/85689/File/47476801615.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=an+occurrence+at+owl+creek+bridge+worksheet+answers
    • 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_off0000e9f3.bin
4db686efb14f0555b59c1d143e87f0367e7b6fb34baa507d9bd02db76f95ba36
pdf-font-stream PDF embedded font (sfnt) at offset 0xE9F3 11048 bytes
font_01_sfnt_off00010377.bin
b8579e4a0383dbf49e4029536c3e6a4d3099ad55456e9cdab23fe45bf18bb02b
pdf-font-stream PDF embedded font (sfnt) at offset 0x10377 17068 bytes
font_02_sfnt_off0001300a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1300A 16792 bytes