Malicious PDF — malware analysis report

Static analysis result for SHA-256 adc6db259ce48b41…

MALICIOUS

PDF

83.0 KB Created: 2021-09-08 23:33:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 5c2682cc77faac3f4bd246962c210ce5 SHA-1: 3b7cb7aacee0fd1c7c321e6b498126660f3b11b3 SHA-256: adc6db259ce48b41c70a3a76d661e50dd759a2d363e9f51c34ef1c247d7e4105
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a link farm directing to numerous other PDF files hosted on various domains, many of which are flagged as potentially compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, and the document body was unreadable, but the heuristic findings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://ing-ka.com/user_img/file/84958770177.pdf In PDF document text
    • http://ottomaniantextile.com/userfiles/file/lukogujotuxamipuvifedi.pdfIn PDF document text
    • http://fkhd.cz/data/img/11696559773.pdfIn PDF document text
    • https://archcosmeticstudio.com.au/wp-content/plugins/super-forms/uploads/php/files/aebe5029ce869d8cee5167294f4d1150/kuxetuboguniwagiruvone.pdfIn PDF document text
    • http://bradzo-ep.com/uploads/files/lejugawebiwejederuxabul.pdfIn PDF document text
    • http://knuhpharm.kr/userfiles/file/20210902221454.pdfIn PDF document text
    • https://saint-florentin.charcutier-traiteur.fr/ckfinder/userfiles/files/57585294260.pdfIn PDF document text
    • https://tonitomov.com/picture/file/tivilabekupuwomawilepe.pdfIn PDF document text
    • https://skl.deindrukdemo.nl/upload/files/30689352209.pdfIn PDF document text
    • https://www.verpoort-bouw.be/wp-content/plugins/formcraft/file-upload/server/content/files/161353f581d71f---jojow.pdfIn PDF document text
    • http://sentezetutmerkezi.com/upload/ckfinder/files/pevidonuxokivurazuzu.pdfIn PDF document text
    • http://meble-tk.pl/userfiles/file/2922712764.pdfIn PDF document text
    • https://daulte.ch/ckfinder/userfiles/files/77160537539.pdfIn PDF document text
    • http://jornalespacoaberto.com/app/webroot/datafiles/editor/files/26611341856.pdfIn PDF document text
    • http://cesishotel.com/res/wysiwyg/file/laben.pdfIn PDF document text
    • http://kozelsk-adm.ru/files/uploads/files/nedovamojovev.pdfIn PDF document text
    • https://littleedupark.com/ckfinder/userfiles/files/76185123237.pdfIn PDF document text
    • https://inprovit.com/ckfinder/userfiles/files/suxerikosesipipixogilane.pdfIn PDF document text
    • http://nbnjl.com/userfiles/files/21488936949.pdfIn PDF document text
    • http://structurecreative.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f616e8d8f2---20632946914.pdfIn PDF document text
    • http://acril.ru/ufiles/files/62232710530.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=unroot+android+emulatorPDF 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_off0000e291.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE291 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000faa8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAA8 10348 bytes
SHA-256: c50861e883b7189b9ff1c445ce4381ceac47270e0beb2c9f618527a198e199ed
font_02_sfnt_off000111ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111EE 17076 bytes
SHA-256: 53ec76754f1df321cd479172f76428240338263a6e4f7542cb032f90e502581c