Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3a2cb65c666b685…

MALICIOUS

PDF

69.8 KB Created: 2021-09-25 16:59:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 4ca4a2d289a860cbd2057d270eb779e8 SHA-1: 07a6b82db0f108a6dd11a398cb7024ce006bb472 SHA-256: a3a2cb65c666b6851ed5aa6d3f0b7444474c4b1bf2cd5994095e35fc10d01414
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which are hosted on disposable domains and appear to be part of a link farm designed to redirect users. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a deliberate attempt to obscure the final malicious destination by using many low-reputation domains. The presence of embedded URLs and the overall structure suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://cructi.ru/uplcv?utm_term=online+es+file+explorer PDF link annotation
    • http://nextlab-semi.com/files/fckeditor/file/kogejudokuvokem.pdfIn PDF document text
    • https://cpsguffanti.it/uploads/file/gujinabaki.pdfIn PDF document text
    • https://bangprice.com/bangprice.com/beta/cms_image/file/xofegajixemitajarosa.pdfIn PDF document text
    • http://tsradviseurs.nl/mailing/images/photo/file/mokesu.pdfIn PDF document text
    • http://studiopiergentili.it/userfiles/files/vawodorizajifuwalixog.pdfIn PDF document text
    • http://www.fotografoeventimilano.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ca7d9e22ad---88511423858.pdfIn PDF document text
    • http://www.ap-arte.ro/fckupload/file/60516025125.pdfIn PDF document text
    • http://olsztyntransportmedyczny.pl/userfiles/file/mineluwakazixenavowibi.pdfIn PDF document text
    • http://kor-ra.ru/UserFiles/file/muzudigimemoreliperufatit.pdfIn PDF document text
    • http://verzorgingsindex.nl/images/uploads/vuroxab.pdfIn PDF document text
    • http://tovicetour.com/FileData/ckfinder/files/20210920_E334C41BE333359E.pdfIn PDF document text
    • http://safeabortionnepal.com/userfiles/file/95606112252.pdfIn PDF document text
    • https://jck.ro/userfiles/file/xomuwemamojerejuburumexa.pdfIn PDF document text
    • https://ijp2.com/contents/files/fewefokevotitare.pdfIn PDF document text
    • http://mcutech.net/files/wonomobovape.pdfIn PDF document text
    • http://uitetenindex.nl/images/uploads/34509637892.pdfIn PDF document text
    • https://daulte.com/ckfinder/userfiles/files/39883925944.pdfIn PDF document text
    • http://hgbs.de/userfiles/file/mopapusozuvo.pdfIn PDF document text
    • https://www.e-oswiata.olesnica.pl/ckfinder/userfiles/files/8280239261.pdfIn PDF document text
    • https://035620126.tw/upload/greenkitchen/files/35950311832.pdfIn PDF document text
    • http://studiocastigli.eu/userfiles/files/katubij.pdfIn PDF document text
    • https://quatden.vn/webroot/img/files/wowenokoxisekawukibi.pdfIn PDF document text
    • http://local-minicab.com/survey/userfiles/files/5735777638.pdfIn PDF document text
    • https://trouver-une-ssii.com/img/pics/files/wuxojinaxogugewubugenazuw.pdfIn PDF document text
    • http://stl-hk.net/userfiles/201903429.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_off0000b059.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB059 10216 bytes
SHA-256: fb409ba5f3b10826ce95090b9c7c194a163fe142975707fc6ea2f634d87c2134
font_01_sfnt_off0000c75e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC75E 16636 bytes
SHA-256: 9d3c12f2d97f453178d45e7df0f9e2adff85fccdd087232714ea0dbc18e3c502
font_02_sfnt_off0000f175.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF175 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1