Malicious PDF — malware analysis report

Static analysis result for SHA-256 b26c8ad832c1fa2b…

MALICIOUS

PDF

74.9 KB Created: 2021-09-06 17:49:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: ce150ce1f2091514d504084731fd8179 SHA-1: 38c78d918c488bc918adf2cb0a69abcac2141961 SHA-256: b26c8ad832c1fa2b74297dee638c67a5bfcdfe7d3940ad429d4d5400a0005b28
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or other potentially malicious hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to lure users to malicious sites through a link farm. No scripts were extracted, and the document body was unreadable, but the URL analysis and heuristic firings are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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
  • 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.asap-recruitment.net/upload/file/difezisimedoboserugizi.pdf In PDF document text
    • https://www.dars.bg/ckfinder/userfiles/files/kidese.pdfIn PDF document text
    • http://kwik-it.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1609e4e470245e---7667226183.pdfIn PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160d661828c87e---87587795365.pdfIn PDF document text
    • http://www.a-fairys-choice.com/wp-content/plugins/formcraft/file-upload/server/content/files/16096737a89cec---vizukixawigekujokowun.pdfIn PDF document text
    • https://law.myvzl.com/wp-content/plugins/super-forms/uploads/php/files/03bvojklc54nt4gdjm3m8d9qrd/riripokibejezekurunonaje.pdfIn PDF document text
    • https://cedarcreeksauce.com/wp-content/plugins/super-forms/uploads/php/files/88893fd8f7c48465c234bf6b31ff1823/51273160603.pdfIn PDF document text
    • https://foursservices.com/nbloom/fckuploads/file/vefowotofiz.pdfIn PDF document text
    • https://morabia.fi/images/file/dufageve.pdfIn PDF document text
    • http://ydyb.com/filespath/files/20210827101550.pdfIn PDF document text
    • https://shared401k.com/wp-content/plugins/super-forms/uploads/php/files/1ca7e8206c5fbcd1610094fcceda98d0/16986751879.pdfIn PDF document text
    • https://hightechrustremovers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161255c1c24c24---lojevodafukabe.pdfIn PDF document text
    • http://www.kliningstroy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16086d2943f271---vavemopuxubidon.pdfIn PDF document text
    • https://www.grecosalesinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/161102970d6dc2---fefimofo.pdfIn PDF document text
    • http://nenorm.com/files/files/8282598808.pdfIn PDF document text
    • http://ore-processing.ru/d/files/77245928266.pdfIn PDF document text
    • http://www.fotografoeventimilano.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ba3caae4acf---nalaruresu.pdfIn PDF document text
    • http://mtegl.wsystem.sk/userfiles/files/safeferenipuligev.pdfIn PDF document text
    • http://elmbbq.com/uploads/files/73827241654.pdfIn PDF document text
    • http://yuseigachi.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608d77fa48be4---9546645897.pdfIn PDF document text
    • http://zuche0551.com/upload/file/nofilafidakut.pdfIn PDF document text
    • http://detikakdeti.ru/img/file/mevenej.pdfIn PDF document text
    • https://llibreriaha.com/img/events/file/17173544966.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=comprehension+worksheet+grade+10PDF 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_off0000c257.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC257 16380 bytes
SHA-256: c52d9ac54c39bd5b9d8d61dcb920de154c54051114d0ef45c50b4e3b3cda1d41
font_01_sfnt_off0000ec3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC3B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010452.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10452 11176 bytes
SHA-256: c71b7428c8f46dc958be3ef21a3aa1a89f23751a2355b8e2a5e0833c763e51d5