Malicious PDF — malware analysis report

Static analysis result for SHA-256 888a558e8f88dd75…

MALICIOUS

PDF

68.2 KB Created: 2021-09-26 03:24:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 24103153cec3742b3ebba2df4bc837b4 SHA-1: 39fec1df9d2bb69794c314888e90ed5daf12ce5d SHA-256: 888a558e8f88dd75cbc9943a25dc16009b0330efbc5705330942f8eb5867314c
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which are part of a link farm on disposable hosting, suggesting a phishing or scam attempt. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM specifically flags this behavior. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware delivery via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://infrive.ru/uplcv?utm_term=how+to+know+who+visited+my+instagram+account PDF link annotation
    • http://xn--bqrr0jw6bmw2g.com/userfiles/file/1632610008.pdfIn PDF document text
    • http://thedewakohchang.com/image/upload/File/0528658899.pdfIn PDF document text
    • https://dol-rtknetwork.com/uploads/files/lanazub.pdfIn PDF document text
    • http://onelove.cz/file/jobowemuxas.pdfIn PDF document text
    • http://kovove-ploty-brany-zabradli.cz/UserFiles/File/61670549400.pdfIn PDF document text
    • https://yodishit.com/uploads/userfiles/file/xifenupagilixuj.pdfIn PDF document text
    • http://kursverwaltung.fit-n-essen.ch/ckfinder/userfiles/files/filikikitizudefagip.pdfIn PDF document text
    • https://fo-prefectures.com/pages/files/rolefojulizepijodegebupe.pdfIn PDF document text
    • http://win-sonic.com/ck_imgs/files/xolitesobu.pdfIn PDF document text
    • http://fcv-bo.org/data/fcv-bo/userfiles/file/47535211729.pdfIn PDF document text
    • http://hfnhsw.com/upload/files/43515447397.pdfIn PDF document text
    • https://tp-pos.com/uploads/image/files/75692138792.pdfIn PDF document text
    • http://0985028898.kad.tw/kads/ckfinder/userfiles/files/vakilawinupi.pdfIn PDF document text
    • http://sterenstein.ru/userfiles/file/49322349492.pdfIn PDF document text
    • http://leap-egypt.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614d49a1bb87f---47607925525.pdfIn PDF document text
    • http://fastbeatbattlerider.saint-fun.com/assets/upload/files/6834862525.pdfIn PDF document text
    • https://nsck-cykelmotion.dk/ckfinder/userfiles/files/matokomelajokifaridikada.pdfIn PDF document text
    • http://geojeoceanhotel.com/userfiles/file/20210917131059.pdfIn PDF document text
    • https://wroclawmodelshow.pl/ckfinder/userfiles/files/bedamusokuwibizusu.pdfIn PDF document text
    • http://topbuild.net/content/xuploadimages/file/59617805954.pdfIn PDF document text
    • http://escalierdurire.fr/ckfinder/userfiles/files/xubibajixuwan.pdfIn PDF document text
    • http://senkyu.jp/webroot/img/files/61723099918.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_off0000ac92.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAC92 11220 bytes
SHA-256: 0b1f6a6e03921c4aad8037554f180b817697ec2d141f857e1aaf57560d9b26c9
font_01_sfnt_off0000c689.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC689 14532 bytes
SHA-256: e727037857d26da6e37e2315cc3f4b087b0120d4373c67a402a085db97a4a733
font_02_sfnt_off0000eb27.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB27 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1