Malicious PDF — malware analysis report

Static analysis result for SHA-256 31c0f15c12d53712…

MALICIOUS

PDF

84.4 KB Created: 2021-09-19 03:47:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: c7f242476892c09b525642c79a14a070 SHA-1: 50806359376c8b93ac26d26d3a19ffadd9f734ca SHA-256: 31c0f15c12d537120938b8a00e6fc1c06f849485f39479734a99b5aae8db8466
126 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to suspicious PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using many distinct, potentially disposable hosts to obscure the true malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://schodylux.pl/userfiles/file/94446958964.pdf In PDF document text
    • http://oilspecchem.com/files/balaferipewodoxuju.pdfIn PDF document text
    • http://pedraferro.com/files/files/gutujo.pdfIn PDF document text
    • https://travellifeafrica.com/ci/userfiles/files/jimimonikiburanipuvumu.pdfIn PDF document text
    • https://hophamthaibinh.com/upload/files/35001957981.pdfIn PDF document text
    • https://bawaniint.com/ckfinder/userfiles/files/samifineta.pdfIn PDF document text
    • http://abwlondonblvd.com/uploads/files/76021360218.pdfIn PDF document text
    • http://tjsijiqing.com/ckfinder/userfiles/files/2021/0902/edce3aed96169e0f570d4da7af3f0337.pdfIn PDF document text
    • http://bfcy88.com/uploads/files/zakup.pdfIn PDF document text
    • http://kcntanduc.vn/img_duhoc/files/depipijoku.pdfIn PDF document text
    • http://kayapaliinsaat.net/file/pigam.pdfIn PDF document text
    • https://www.chablis-gautherin.com/ckfinder/userfiles/files/kaxolajimevekoxi.pdfIn PDF document text
    • http://apsons.eu/files/file/46853709041.pdfIn PDF document text
    • http://xn--m1age8bh.xn--p1ai/files/file/miwabowojaba.pdfIn PDF document text
    • https://suma.ca/upload/editor/file/23004410852.pdfIn PDF document text
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613cf089f1457---bumenolodalu.pdfIn PDF document text
    • http://rayanchem.com/d/files/binoku.pdfIn PDF document text
    • http://autoscuolauniversale.it/userfiles/files/jojuluzojaxijesepeb.pdfIn PDF document text
    • https://feltshoe.com/userfiles/file/25413328050.pdfIn PDF document text
    • http://3dprofi.net/images/uploads/file/guvadotegabilotiludomina.pdfIn PDF document text
    • http://tznjl.com/userfiles/files/puwafonebexofapoxex.pdfIn PDF document text
    • https://tessuno.com/upload/files/613fea7f12cd8.pdfIn PDF document text
    • http://www.keizerco.nl/userFiles/file/19859525852.pdfIn PDF document text
    • http://thangmayedex.com/webroot/img/files/49576475509.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=once+upon+time+in+bihar+full+moviePDF 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_off0000e578.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE578 17788 bytes
SHA-256: b70c5b775913b807523e2580f60c464fe9c18045ddb7a0e17e3d8d9840968124
font_01_sfnt_off00011300.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11300 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012b17.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12B17 10908 bytes
SHA-256: ec3bd0477a1a8aead981eab3295b79a8d13ea64650fced123f810b71392cccff