Malicious PDF — malware analysis report

Static analysis result for SHA-256 91ec05b477dcca5e…

MALICIOUS

PDF

78.0 KB Created: 2021-09-01 12:13:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 92ccdf2f190ed4faf5ee6751b044a57a SHA-1: ff5f43f0aba2dad2285f776cf5a54b7f2570df7c SHA-256: 91ec05b477dcca5eb610433f5606645f3ea6e3ded46a7d0948447e0420524b66
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous links pointing to various domains, many of which appear to be compromised CMS uploads or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct user-facing content, but the heuristic firings clearly point to a link farm strategy.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://poltinik.ru/userfiles/file/77170538246.pdf
    • https://rebates.forex/wp-content/plugins/super-forms/uploads/php/files/431mpnoi0oa0eopuf4e7e9tr33/19345546524.pdf
    • https://celovechurch.org/wp-content/plugins/super-forms/uploads/php/files/f7159c1282fa017d052a98d6426239dd/49308752353.pdf
    • http://gmei.lt/ckfinder/userfiles/files/69536226310.pdf
    • https://www.pennlighting.com/wp-content/plugins/super-forms/uploads/php/files/2dd17fbf175da60ccfed7ad23c2d619d/78195436165.pdf
    • http://immodraft.nrw/images/architekten_agentur_images_/file/74732147993.pdf
    • https://www.focus.mu/wp-content/plugins/super-forms/uploads/php/files/04fe0a59b41f4d2a2319dd502b895ec7/botekunopu.pdf
    • https://www.libyamonitor.com/sites/all/libraries/ckfinder/userfiles/files/xewilipekofiju.pdf
    • https://mkting.com.co/wp-content/plugins/super-forms/uploads/php/files/0d6ddbb10a45d171e64320e90eeef72b/45782029019.pdf
    • http://opalbiosciences.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081b1d46434a---9394855907.pdf
    • http://intertexmedical.com/userfiles/files/nifujutizufu.pdf
    • https://calmoinc.com/upload/editor/file/ruzofaliduxul.pdf
    • http://jmk.kr/ckfinder/userfiles/files/67675303641.pdf
    • https://ruedi-leuthold.com/userfiles/files/94904769860.pdf
    • http://toyotarent.hk/FileData/ckfinder/files/20210901_DE46AAE51F7F4FDC.pdf
    • https://littleedupark.com/ckfinder/userfiles/files/zejuziguvulowaxum.pdf
    • http://miamiwars.pl/wp-content/plugins/super-forms/uploads/php/files/c0dc75520007a5e92708ba3656a0d29d/13964997916.pdf
    • https://gospel-streams.com/asset/ckfinder/userfiles/files/kugur.pdf
    • https://jodhpurtravels.com/nbloom/fckuploads/file/21207676656.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160926c28b1bf4---80358202787.pdf
    • http://totoquynhhuong.com/upload/files/gopuridebozafowazesirodiz.pdf
    • http://studioscoponi.eu/userfiles/files/62480645640.pdf
    • http://asiavent.com/UserFiles/file///9499159904.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=gowdy+for+president
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cc50.bin
1476964b3f0a3223e27d4856640742b996c208d80e25b2a80b302262437e6004
pdf-font-stream PDF embedded font (sfnt) at offset 0xCC50 10520 bytes
font_01_sfnt_off0000e47c.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE47C 16792 bytes
font_02_sfnt_off0000fc8e.bin
3ad805b2c1a24d14fde47b4b1ac9aed4e06a6e60855adbe6ef9a56d5189261d7
pdf-font-stream PDF embedded font (sfnt) at offset 0xFC8E 18144 bytes