Malicious PDF — malware analysis report

Static analysis result for SHA-256 52b823ed9bae4b3c…

MALICIOUS

PDF

41.8 KB Created: 2020-08-30 17:17:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 20e4d6d8413c8edcbfbcd0276297e4db SHA-1: e56154010e344a11e918bd82d4ea31ee66155ea8 SHA-256: 52b823ed9bae4b3c25781cef717c32961804a8a0e2b665a4bdf96bd65a253fc9
154 Risk Score

Malware Insights

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

The PDF contains a mass external link farm, with many links pointing to benign-looking documents hosted on Shopify and other platforms. However, one critical link directs to a known malicious redirector at `ttraff.cc`. The document body, though garbled, contains text related to 'addition worksheets with regrouping 2nd grade', suggesting a lure to disguise the malicious intent. The ML classifier strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://ttraff.cc/wix?keyword=addition+worksheets+with+regrouping+2nd+grade
    • https://static.usrfiles.com/ugd/a48928_4cf2f8e66ba745c797c42024980af006.pdf
    • https://static.usrfiles.com/ugd/b8c837_bbb42eef0c7743daa41a1dd219d3782d.pdf
    • https://static.usrfiles.com/ugd/b8c837_e5adc04bb8e148e19018b756e5eab315.pdf
    • https://static.usrfiles.com/ugd/d94ae5_8aa6e610f09d46f8b4b8ad65e5282ac9.pdf
    • https://static.usrfiles.com/ugd/ea5d7b_effd7d31968943f38fd9c77e1e711f60.pdf
    • https://cdn.shopify.com/s/files/1/0463/4030/9153/files/valafanebinugibajeji.pdf
    • https://cdn.shopify.com/s/files/1/0437/3315/6001/files/76610563456.pdf
    • https://cdn.shopify.com/s/files/1/0431/4651/0504/files/72561724809.pdf
    • https://cdn.shopify.com/s/files/1/0432/0441/1556/files/callus_formation_bone_remodeling.pdf
    • https://cdn.shopify.com/s/files/1/0432/5031/9517/files/mogipuzupepabuxudizalodit.pdf
    • https://cdn.shopify.com/s/files/1/0433/7650/9080/files/bloons_td_6_apk_v_1._6.pdf
    • https://cdn.shopify.com/s/files/1/0432/7643/5621/files/factorio_steel_smelting.pdf
    • https://cdn.shopify.com/s/files/1/0427/4293/9814/files/sunibix.pdf
    • https://static.usrfiles.com/ugd/b8c837_32af411ec13b4b5586ca4b5e2a8b5380.pdf
    • https://static.usrfiles.com/ugd/b8c837_85462f0433d7413e9710f054460c3c46.pdf
    • https://static.usrfiles.com/ugd/c0b427_ebe14bca2e5747698cbd94ffcd0e62de.pdf
    • https://static.usrfiles.com/ugd/e3c460_823370f2123845eb8dc017ef67cf047d.pdf
    • https://static.usrfiles.com/ugd/3bf302_6959fb74cd2f47b9bdc4adcd6231a183.pdf
    • 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/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000063b4.bin
0fe7ccc8ed18c47e7cb267b53450e058cf1da46fd2451a3c2da37ec246979ded		 pdf-font-stream PDF embedded font (sfnt) at offset 0x63B4 5468 bytes
font_01_sfnt_off0000765b.bin
e1dcc31897502d7dc110c8d9b3e2648c57ea6254cce1033c4734323106e985fe		 pdf-font-stream PDF embedded font (sfnt) at offset 0x765B 10352 bytes

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