Malicious PDF — malware analysis report

Static analysis result for SHA-256 785a533f167ab0f8…

MALICIOUS

PDF

83.7 KB Created: 2021-09-17 03:45:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: cfbb5d39fed6227420782e790f4a9be3 SHA-1: d434238cbee3f3e4d7f5e55c666d75cb5e471091 SHA-256: 785a533f167ab0f8fb873c91ad45ba28f2927c4785b992e4915df24bf3935dbb
142 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains embedded JavaScript, which is often used to exploit PDF vulnerabilities or redirect users. The presence of numerous external URIs, including one pointing to 'pistant.ru', suggests a phishing or malware distribution attempt. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further indicating a non-legitimate purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://pistant.ru/uplcv?utm_term=install+chrome+os+with+play+store+on+pc PDF link annotation
    • http://mabifitness.it/userfiles/files/veridadoxajanuloni.pdfIn PDF document text
    • http://www.fan-consultants.com.tw/ezadmin/ckfinder/userfiles/files/19197174618.pdfIn PDF document text
    • http://business-plan-capalpha.eu/mbp/upload/images/images/upload/ckfinder/nudiwunotajamanelosulomax.pdfIn PDF document text
    • https://interference.ajoda.eu/userfiles/files/tabosuwebogafirixudineriv.pdfIn PDF document text
    • http://geodeslaboratori.eu/userfiles/files/15115837683.pdfIn PDF document text
    • https://ccveg.org/wp-content/plugins/super-forms/uploads/php/files/gtp6fgu1mmcde9b1kou4b7p6si/nigibota.pdfIn PDF document text
    • http://mansiya.com/uploadfile/files/rafovadaxef.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f219663f88---terusiwewunoluk.pdfIn PDF document text
    • http://motivationandmomentum.net/ci/userfiles/files/xufaw.pdfIn PDF document text
    • http://balogmihaly.hu/UserFiles/file/nitudilifukukelimodeguxa.pdfIn PDF document text
    • http://mwbright.com/upload_fck/file/2021-9-9/20210909235917861275.pdfIn PDF document text
    • http://maezawa-jidousha.com/js/upload/files/97926605207.pdfIn PDF document text
    • http://paulbwatkinslaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/pabexutukinopovunofof.pdfIn PDF document text
    • http://elitk.ru/_files/ponavajamazatumiwa.pdfIn PDF document text
    • http://momsystem.ru/public/file/tumapalom.pdfIn PDF document text
    • https://fotobolfestmeny.hu/mvc/userfiles/file/64255387962.pdfIn PDF document text
    • http://yigang-lin.com/uploads/files/202109021324548507.pdfIn PDF document text
    • https://newtech-utm.pl/userfiles/file/79980827225.pdfIn PDF document text
    • http://xn--zb0bw3kv4s8mn.com/upload/fckeditor/file/57887938484.pdfIn PDF document text
    • https://mobilieroccasion.fr/uploads/file/82638047035.pdfIn PDF document text
    • https://discovercefalu.it/_data/images/file/fowofosok.pdfIn PDF document text
    • https://aczv.fr/userfiles/file/36099020007.pdfIn PDF document text
    • http://mstreatmentadvances.com/userfiles/files/lamozoparurevibija.pdfIn PDF document text
    • https://doellefjelde-mussemarked.dk/images/newsmail/file/27758574889.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_off0000e0b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0B1 18188 bytes
SHA-256: a7c71e90300ca4b620202c10924b095f4ac8a41ddfe965c7241cc03d911b5e12
font_01_sfnt_off00010fad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10FAD 10792 bytes
SHA-256: 281335308377abc11805aebc90a45ebbac20aae1119bfca08c5b92916686d8a1
font_02_sfnt_off0001286d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1286D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1