Malicious PDF — malware analysis report

Static analysis result for SHA-256 23b16e2dc8c9f8ef…

MALICIOUS

PDF

78.1 KB Created: 2021-10-09 15:24:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 0fece8569bff8a5fffee3e432679daa7 SHA-1: 091b781a36d4b8d8cede0712ab2a932b1924559a SHA-256: 23b16e2dc8c9f8ef652fb82bdf6e7b5f83027044bbf126d8a1db011d0841ecd7
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 high likelihood of malicious intent. Heuristics reveal it functions as a link farm, with numerous embedded URLs pointing to external sites, some hosted on compromised CMS uploads. The document body is heavily obfuscated and unreadable, suggesting it's not intended for user interaction but rather to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 http://www.specemc.ru/upload/files/64603862399.pdf In PDF document text
    • http://texmet.pl/userimages/file/larazavorezi.pdfIn PDF document text
    • http://hbaoge.com/upload/files/xujubofozuduxorotamexa.pdfIn PDF document text
    • https://eravukappalpalli.com/userfiles/file/80484970030.pdfIn PDF document text
    • http://phone-server.com/userfiles/file/44504809133.pdfIn PDF document text
    • https://excellencetogether.com/img/files/file/lazomosukesoxugexonifip.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614d9f476a93c---zuxitu.pdfIn PDF document text
    • https://goooinggroup.com/userfiles/files/20210911_055629.pdfIn PDF document text
    • https://www.toptalentusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615c9dab023c4---kezalojepiriguxumirire.pdfIn PDF document text
    • http://mauchlineware.com/html/chapelstreet/web/userfiles/files/powuvaburaluruzuwane.pdfIn PDF document text
    • https://tecnibat.net/uploads/archivos/97310089913.pdfIn PDF document text
    • https://el-tall.pl/pics/file/9954850258.pdfIn PDF document text
    • https://yennenga.org/business_school/uploads/file/bobuwukasulitosu.pdfIn PDF document text
    • https://vpmemorial.net/images/file/23567944268.pdfIn PDF document text
    • http://raczcsalad.hu/files/lamizifabofanizuv.pdfIn PDF document text
    • https://hexema.com/FCKeditor/file/15317159941.pdfIn PDF document text
    • http://nfc.soo.jp/file/40593784368.pdfIn PDF document text
    • https://shindah.com/images/ckeditor_img/files/fezenir.pdfIn PDF document text
    • http://www.hgekc.com/media/userfiles/file/72412452822.pdfIn PDF document text
    • https://noks.cz/wp-content/plugins/formcraft/file-upload/server/content/files/1613b99f35739b---38813644600.pdfIn PDF document text
    • https://www.techsrollout.com/wp-content/plugins/formcraft/file-upload/server/content/files/16160944a4cbb2---46154692068.pdfIn PDF document text
    • http://mptech.vn/ckfinder/userfiles/files/zarolaruzetakogovutag.pdfIn PDF document text
    • http://www.hangmandigital.com/files/file/73111718524.pdfIn PDF document text
    • https://popcouncilinstitute.org/wp-content/plugins/super-forms/uploads/php/files/b8ebccc4259c00bb37a922256ddbd7a4/19099850573.pdfIn PDF document text
    • http://orderbestwings.com/uploads/files/37148562206.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=boat+race+2021+timetablePDF 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_off0000cc3f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC3F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e451.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE451 17656 bytes
SHA-256: adf6b9def03da2bac330abe96cf4f2e017f134823b1ec161a9ccd69eead23855
font_02_sfnt_off00011241.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11241 10608 bytes
SHA-256: f8e6b3b6eed98ee148762595f8891b72fdbedf015b7a59585433fabf4c69ead2

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